The reconstruction of a continuous two-stranded DNA molecule without mismatch from a molecule which contained damaged regions. The major repair mechanisms are excision repair, in which defective regions in one strand are excised and resynthesized using the complementary base pairing information in the intact strand; photoreactivation repair, in which the lethal and mutagenic effects of ultraviolet light are eliminated; and post-replication repair, in which the primary lesions are not repaired, but the gaps in one daughter duplex are filled in by incorporation of portions of the other (undamaged) daughter duplex. Excision repair and post-replication repair are sometimes referred to as "dark repair" because they do not require light.

Immunologically detectable substances found in the CELL NUCLEUS.

Interruptions in the sugar-phosphate backbone of DNA, across both strands adjacently.

Enzymes that are involved in the reconstruction of a continuous two-stranded DNA molecule without mismatch from a molecule, which contained damaged regions.

The repair of DOUBLE-STRAND DNA BREAKS by rejoining the broken ends of DNA to each other directly.

Injuries to DNA that introduce deviations from its normal, intact structure and which may, if left unrepaired, result in a MUTATION or a block of DNA REPLICATION. These deviations may be caused by physical or chemical agents and occur by natural or unnatural, introduced circumstances. They include the introduction of illegitimate bases during replication or by deamination or other modification of bases; the loss of a base from the DNA backbone leaving an abasic site; single-strand breaks; double strand breaks; and intrastrand (PYRIMIDINE DIMERS) or interstrand crosslinking. Damage can often be repaired (DNA REPAIR). If the damage is extensive, it can induce APOPTOSIS.

Poly(deoxyribonucleotide):poly(deoxyribonucleotide)ligases. Enzymes that catalyze the joining of preformed deoxyribonucleotides in phosphodiester linkage during genetic processes during repair of a single-stranded break in duplex DNA. The class includes both EC 6.5.1.1 (ATP) and EC 6.5.1.2 (NAD).

A serine-threonine protein kinase that, when activated by DNA, phosphorylates several DNA-binding protein substrates including the TUMOR SUPPRESSOR PROTEIN P53 and a variety of TRANSCRIPTION FACTORS.

Proteins which bind to DNA. The family includes proteins which bind to both double- and single-stranded DNA and also includes specific DNA binding proteins in serum which can be used as markers for malignant diseases.

A deoxyribonucleotide polymer that is the primary genetic material of all cells. Eukaryotic and prokaryotic organisms normally contain DNA in a double-stranded state, yet several important biological processes transiently involve single-stranded regions. DNA, which consists of a polysugar-phosphate backbone possessing projections of purines (adenine and guanine) and pyrimidines (thymine and cytosine), forms a double helix that is held together by hydrogen bonds between these purines and pyrimidines (adenine to thymine and guanine to cytosine).

Proteins that catalyze the unwinding of duplex DNA during replication by binding cooperatively to single-stranded regions of DNA or to short regions of duplex DNA that are undergoing transient opening. In addition DNA helicases are DNA-dependent ATPases that harness the free energy of ATP hydrolysis to translocate DNA strands.

A family of enzymes that catalyze the exonucleolytic cleavage of DNA. It includes members of the class EC 3.1.11 that produce 5'-phosphomonoesters as cleavage products.

Production of new arrangements of DNA by various mechanisms such as assortment and segregation, CROSSING OVER; GENE CONVERSION; GENETIC TRANSFORMATION; GENETIC CONJUGATION; GENETIC TRANSDUCTION; or mixed infection of viruses.

A group of enzymes catalyzing the endonucleolytic cleavage of DNA. They include members of EC 3.1.21.-, EC 3.1.22.-, EC 3.1.23.- (DNA RESTRICTION ENZYMES), EC 3.1.24.- (DNA RESTRICTION ENZYMES), and EC 3.1.25.-.

Proteins found in the nucleus of a cell. Do not confuse with NUCLEOPROTEINS which are proteins conjugated with nucleic acids, that are not necessarily present in the nucleus.

A single chain of deoxyribonucleotides that occurs in some bacteria and viruses. It usually exists as a covalently closed circle.

The sequence of PURINES and PYRIMIDINES in nucleic acids and polynucleotides. It is also called nucleotide sequence.

A DNA repair pathway involved in correction of errors introduced during DNA replication when an incorrect base, which cannot form hydrogen bonds with the corresponding base in the parent strand, is incorporated into the daughter strand. Excinucleases recognize the BASE PAIR MISMATCH and cause a segment of polynucleotide chain to be excised from the daughter strand, thereby removing the mismatched base. (from Oxford Dictionary of Biochemistry and Molecular Biology, 2001)

An exchange of DNA between matching or similar sequences.

Repair of DNA DAMAGE by exchange of DNA between matching sequences, usually between the allelic DNA (ALLELES) of sister chromatids.

Descriptions of specific amino acid, carbohydrate, or nucleotide sequences which have appeared in the published literature and/or are deposited in and maintained by databanks such as GENBANK, European Molecular Biology Laboratory (EMBL), National Biomedical Research Foundation (NBRF), or other sequence repositories.

That portion of the electromagnetic spectrum immediately below the visible range and extending into the x-ray frequencies. The longer wavelengths (near-UV or biotic or vital rays) are necessary for the endogenous synthesis of vitamin D and are also called antirachitic rays; the shorter, ionizing wavelengths (far-UV or abiotic or extravital rays) are viricidal, bactericidal, mutagenic, and carcinogenic and are used as disinfectants.

Any detectable and heritable change in the genetic material that causes a change in the GENOTYPE and which is transmitted to daughter cells and to succeeding generations.

Enzymes that catalyze the hydrolysis of the internal bonds and thereby the formation of polynucleotides or oligonucleotides from ribo- or deoxyribonucleotide chains. EC 3.1.-.

Proteins obtained from the species SACCHAROMYCES CEREVISIAE. The function of specific proteins from this organism are the subject of intense scientific interest and have been used to derive basic understanding of the functioning similar proteins in higher eukaryotes.

Deoxyribonucleic acid that makes up the genetic material of fungi.

A terminal section of a chromosome which has a specialized structure and which is involved in chromosomal replication and stability. Its length is believed to be a few hundred base pairs.

Interruptions in one of the strands of the sugar-phosphate backbone of double-stranded DNA.

A Rec A recombinase found in eukaryotes. Rad51 is involved in DNA REPAIR of double-strand breaks.

A DNA-binding protein that mediates DNA REPAIR of double strand breaks, and HOMOLOGOUS RECOMBINATION.

A species of the genus SACCHAROMYCES, family Saccharomycetaceae, order Saccharomycetales, known as "baker's" or "brewer's" yeast. The dried form is used as a dietary supplement.

An abnormal balloon- or sac-like dilatation in the wall of the ABDOMINAL AORTA which gives rise to the visceral, the parietal, and the terminal (iliac) branches below the aortic hiatus at the diaphragm.

Insertion of viral DNA into host-cell DNA. This includes integration of phage DNA into bacterial DNA; (LYSOGENY); to form a PROPHAGE or integration of retroviral DNA into cellular DNA to form a PROVIRUS.

An increased tendency of the GENOME to acquire MUTATIONS when various processes involved in maintaining and replicating the genome are dysfunctional.

A family of structurally-related DNA helicases that play an essential role in the maintenance of genome integrity. RecQ helicases were originally discovered in E COLI and are highly conserved across both prokaryotic and eukaryotic organisms. Genetic mutations that result in loss of RecQ helicase activity gives rise to disorders that are associated with CANCER predisposition and premature aging.

The process by which a DNA molecule is duplicated.

A group of enzymes that catalyzes the phosphorylation of serine or threonine residues in proteins, with ATP or other nucleotides as phosphate donors.

ELECTROMAGNETIC RADIATION or particle radiation (high energy ELEMENTARY PARTICLES) capable of directly or indirectly producing IONS in its passage through matter. The wavelengths of ionizing electromagnetic radiation are equal to or smaller than those of short (far) ultraviolet radiation and include gamma and X-rays.

Water-soluble, copper-containing low molecular weight polypeptides obtained from the culture medium of Streptomyces verticillus. They are specific inhibitors of DNA synthesis in bacteria and have been found to act as antitumor agents. They have also been used against rust fungi of plants.

Interruptions in the sugar-phosphate backbone of DNA.

Restoration of integrity to traumatized tissue.

The process in which substances, either endogenous or exogenous, bind to proteins, peptides, enzymes, protein precursors, or allied compounds. Specific protein-binding measures are often used as assays in diagnostic assessments.

A single-stranded DNA-binding protein that is found in EUKARYOTIC CELLS. It is required for DNA REPLICATION; DNA REPAIR; and GENETIC RECOMBINATION.

A group of PROTEIN-SERINE-THREONINE KINASES which activate critical signaling cascades in double strand breaks, APOPTOSIS, and GENOTOXIC STRESS such as ionizing ultraviolet A light, thereby acting as a DNA damage sensor. These proteins play a role in a wide range of signaling mechanisms in cell cycle control.

A species of gram-negative, facultatively anaerobic, rod-shaped bacteria (GRAM-NEGATIVE FACULTATIVELY ANAEROBIC RODS) commonly found in the lower part of the intestine of warm-blooded animals. It is usually nonpathogenic, but some strains are known to produce DIARRHEA and pyogenic infections. Pathogenic strains (virotypes) are classified by their specific pathogenic mechanisms such as toxins (ENTEROTOXIGENIC ESCHERICHIA COLI), etc.

Proteins that specifically bind to TELOMERES. Proteins in this class include those that perform functions such as telomere capping, telomere maintenance and telomere stabilization.

An ATP-dependent exodeoxyribonuclease that cleaves in either the 5'- to 3'- or the 3'- to 5'-direction to yield 5'-phosphooligonucleotides. It is primarily found in BACTERIA.

Surgical insertion of BLOOD VESSEL PROSTHESES to repair injured or diseased blood vessels.

The process by which the V (variable), D (diversity), and J (joining) segments of IMMUNOGLOBULIN GENES or T-CELL RECEPTOR GENES are assembled during the development of LYMPHOID CELLS using NONHOMOLOGOUS DNA END-JOINING.

A DNA repair enzyme that catalyzes DNA synthesis during base excision DNA repair. EC 2.7.7.7.

Recombinases that insert exogenous DNA into the host genome. Examples include proteins encoded by the POL GENE of RETROVIRIDAE and also by temperate BACTERIOPHAGES, the best known being BACTERIOPHAGE LAMBDA.

The presence of an uncomplimentary base in double-stranded DNA caused by spontaneous deamination of cytosine or adenine, mismatching during homologous recombination, or errors in DNA replication. Multiple, sequential base pair mismatches lead to formation of heteroduplex DNA; (NUCLEIC ACID HETERODUPLEXES).

The spatial arrangement of the atoms of a nucleic acid or polynucleotide that results in its characteristic 3-dimensional shape.

Proteins that control the CELL DIVISION CYCLE. This family of proteins includes a wide variety of classes, including CYCLIN-DEPENDENT KINASES, mitogen-activated kinases, CYCLINS, and PHOSPHOPROTEIN PHOSPHATASES as well as their putative substrates such as chromatin-associated proteins, CYTOSKELETAL PROTEINS, and TRANSCRIPTION FACTORS.

A type of chromosomal aberration involving DNA BREAKS. Chromosome breakage can result in CHROMOSOMAL TRANSLOCATION; CHROMOSOME INVERSION; or SEQUENCE DELETION.

Elements of limited time intervals, contributing to particular results or situations.

Extrachromosomal, usually CIRCULAR DNA molecules that are self-replicating and transferable from one organism to another. They are found in a variety of bacterial, archaeal, fungal, algal, and plant species. They are used in GENETIC ENGINEERING as CLONING VECTORS.

A family of DNA repair enzymes that recognize damaged nucleotide bases and remove them by hydrolyzing the N-glycosidic bond that attaches them to the sugar backbone of the DNA molecule. The process called BASE EXCISION REPAIR can be completed by a DNA-(APURINIC OR APYRIMIDINIC SITE) LYASE which excises the remaining RIBOSE sugar from the DNA.

Enzymes that catalyze the release of mononucleotides by the hydrolysis of the terminal bond of deoxyribonucleotide or ribonucleotide chains.

The ability of some cells or tissues to survive lethal doses of IONIZING RADIATION. Tolerance depends on the species, cell type, and physical and chemical variables, including RADIATION-PROTECTIVE AGENTS and RADIATION-SENSITIZING AGENTS.

Established cell cultures that have the potential to propagate indefinitely.

The first continuously cultured human malignant CELL LINE, derived from the cervical carcinoma of Henrietta Lacks. These cells are used for VIRUS CULTIVATION and antitumor drug screening assays.

Enzyme of the HUMAN IMMUNODEFICIENCY VIRUS that is required to integrate viral DNA into cellular DNA in the nucleus of a host cell. HIV integrase is a DNA nucleotidyltransferase encoded by the pol gene.

Theoretical representations that simulate the behavior or activity of genetic processes or phenomena. They include the use of mathematical equations, computers, and other electronic equipment.

Exons that are created in vivo during LYMPHOCYTE maturation from the V, D, and J gene segments of immunoglobulin superfamily genes (e.g., the IMMUNOGLOBULIN HEAVY CHAIN GENES, or the T-CELL RECEPTOR BETA GENES or T-CELL RECEPTOR GAMMA GENES ) by the VDJ RECOMBINASE system.

Dimers found in DNA chains damaged by ULTRAVIOLET RAYS. They consist of two adjacent PYRIMIDINE NUCLEOTIDES, usually THYMINE nucleotides, in which the pyrimidine residues are covalently joined by a cyclobutane ring. These dimers block DNA REPLICATION.

Enzymes that catalyze the incorporation of deoxyribonucleotides into a chain of DNA. EC 2.7.7.-.

Deoxyribonucleic acid that makes up the genetic material of viruses.

The order of amino acids as they occur in a polypeptide chain. This is referred to as the primary structure of proteins. It is of fundamental importance in determining PROTEIN CONFORMATION.

Polymers made up of a few (2-20) nucleotides. In molecular genetics, they refer to a short sequence synthesized to match a region where a mutation is known to occur, and then used as a probe (OLIGONUCLEOTIDE PROBES). (Dorland, 28th ed)

DNA-dependent DNA polymerases found in bacteria, animal and plant cells. During the replication process, these enzymes catalyze the addition of deoxyribonucleotide residues to the end of a DNA strand in the presence of DNA as template-primer. They also possess exonuclease activity and therefore function in DNA repair.

Techniques for securing together the edges of a wound, with loops of thread or similar materials (SUTURES).

An enzyme that catalyzes the transfer of a phosphate group to the 5'-terminal hydroxyl groups of DNA and RNA. EC 2.7.1.78.

Evaluation undertaken to assess the results or consequences of management and procedures used in combating disease in order to determine the efficacy, effectiveness, safety, and practicability of these interventions in individual cases or series.

Preparations of cell constituents or subcellular materials, isolates, or substances.

A characteristic feature of enzyme activity in relation to the kind of substrate on which the enzyme or catalytic molecule reacts.

Small chromosomal proteins (approx 12-20 kD) possessing an open, unfolded structure and attached to the DNA in cell nuclei by ionic linkages. Classification into the various types (designated histone I, histone II, etc.) is based on the relative amounts of arginine and lysine in each.

A subfamily in the family MURIDAE, comprising the hamsters. Four of the more common genera are Cricetus, CRICETULUS; MESOCRICETUS; and PHODOPUS.

Penetrating, high-energy electromagnetic radiation emitted from atomic nuclei during NUCLEAR DECAY. The range of wavelengths of emitted radiation is between 0.1 - 100 pm which overlaps the shorter, more energetic hard X-RAYS wavelengths. The distinction between gamma rays and X-rays is based on their radiation source.

An abdominal hernia with an external bulge in the GROIN region. It can be classified by the location of herniation. Indirect inguinal hernias occur through the internal inguinal ring. Direct inguinal hernias occur through defects in the ABDOMINAL WALL (transversalis fascia) in Hesselbach's triangle. The former type is commonly seen in children and young adults; the latter in adults.

Recombinases involved in the rearrangement of immunity-related GENES such as IMMUNOGLOBULIN GENES and T-CELL RECEPTOR GENES.

A DNA repair enzyme that catalyses the excision of ribose residues at apurinic and apyrimidinic DNA sites that can result from the action of DNA GLYCOSYLASES. The enzyme catalyzes a beta-elimination reaction in which the C-O-P bond 3' to the apurinic or apyrimidinic site in DNA is broken, leaving a 3'-terminal unsaturated sugar and a product with a terminal 5'-phosphate. This enzyme was previously listed under EC 3.1.25.2.

A rare, pigmentary, and atrophic autosomal recessive disease. It is manifested as an extreme photosensitivity to ULTRAVIOLET RAYS as the result of a deficiency in the enzyme that permits excisional repair of ultraviolet-damaged DNA.

Enzymes which catalyze the hydrolases of ester bonds within DNA. EC 3.1.-.

A family of recombinases initially identified in BACTERIA. They catalyze the ATP-driven exchange of DNA strands in GENETIC RECOMBINATION. The product of the reaction consists of a duplex and a displaced single-stranded loop, which has the shape of the letter D and is therefore called a D-loop structure.

Theoretical representations that simulate the behavior or activity of biological processes or diseases. For disease models in living animals, DISEASE MODELS, ANIMAL is available. Biological models include the use of mathematical equations, computers, and other electronic equipment.

The tearing or bursting of the wall along any portion of the AORTA, such as thoracic or abdominal. It may result from the rupture of an aneurysm or it may be due to TRAUMA.

A ZINC FINGER MOTIF protein that recognizes and interacts with damaged DNA. It is a DNA-binding protein that plays an essential role in NUCLEOTIDE EXCISION REPAIR. Mutations in this protein are associated with the most severe form of XERODERMA PIGMENTOSUM.

CELL LINE derived from the ovary of the Chinese hamster, Cricetulus griseus (CRICETULUS). The species is a favorite for cytogenetic studies because of its small chromosome number. The cell line has provided model systems for the study of genetic alterations in cultured mammalian cells.

Enzymes that catalyze the transfer of multiple ADP-RIBOSE groups from nicotinamide-adenine dinucleotide (NAD) onto protein targets, thus building up a linear or branched homopolymer of repeating ADP-ribose units i.e., POLY ADENOSINE DIPHOSPHATE RIBOSE.

An abnormal balloon- or sac-like dilatation in the wall of the THORACIC AORTA. This proximal descending portion of aorta gives rise to the visceral and the parietal branches above the aortic hiatus at the diaphragm.

Device constructed of either synthetic or biological material that is used for the repair of injured or diseased blood vessels.

The rate dynamics in chemical or physical systems.

Enzymes that recombine DNA segments by a process which involves the formation of a synapse between two DNA helices, the cleavage of single strands from each DNA helix and the ligation of a DNA strand from one DNA helix to the other. The resulting DNA structure is called a Holliday junction which can be resolved by DNA REPLICATION or by HOLLIDAY JUNCTION RESOLVASES.

MutS homolog 2 protein is found throughout eukaryotes and is a homolog of the MUTS DNA MISMATCH-BINDING PROTEIN. It plays an essential role in meiotic RECOMBINATION and DNA REPAIR of mismatched NUCLEOTIDES.

The region of DNA which borders the 3' end of a transcription unit and where a variety of regulatory sequences are located.

Connective tissue cells which secrete an extracellular matrix rich in collagen and other macromolecules.

The parts of a macromolecule that directly participate in its specific combination with another molecule.

A nucleic acid sequence that contains an above average number of ADENINE and THYMINE bases.

Proteins obtained from ESCHERICHIA COLI.

The level of protein structure in which combinations of secondary protein structures (alpha helices, beta sheets, loop regions, and motifs) pack together to form folded shapes called domains. Disulfide bridges between cysteines in two different parts of the polypeptide chain along with other interactions between the chains play a role in the formation and stabilization of tertiary structure. Small proteins usually consist of only one domain but larger proteins may contain a number of domains connected by segments of polypeptide chain which lack regular secondary structure.

Short sequences (generally about 10 base pairs) of DNA that are complementary to sequences of messenger RNA and allow reverse transcriptases to start copying the adjacent sequences of mRNA. Primers are used extensively in genetic and molecular biology techniques.

Macromolecular complexes formed from the association of defined protein subunits.

Within a eukaryotic cell, a membrane-limited body which contains chromosomes and one or more nucleoli (CELL NUCLEOLUS). The nuclear membrane consists of a double unit-type membrane which is perforated by a number of pores; the outermost membrane is continuous with the ENDOPLASMIC RETICULUM. A cell may contain more than one nucleus. (From Singleton & Sainsbury, Dictionary of Microbiology and Molecular Biology, 2d ed)

Enzyme systems containing a single subunit and requiring only magnesium for endonucleolytic activity. The corresponding modification methylases are separate enzymes. The systems recognize specific short DNA sequences and cleave either within, or at a short specific distance from, the recognition sequence to give specific double-stranded fragments with terminal 5'-phosphates. Enzymes from different microorganisms with the same specificity are called isoschizomers. EC 3.1.21.4.

Radiographic visualization of the aorta and its branches by injection of contrast media, using percutaneous puncture or catheterization procedures.

Cells propagated in vitro in special media conducive to their growth. Cultured cells are used to study developmental, morphologic, metabolic, physiologic, and genetic processes, among others.

Proteins that are normally involved in holding cellular growth in check. Deficiencies or abnormalities in these proteins may lead to unregulated cell growth and tumor development.

Deoxyribonucleic acid that makes up the genetic material of bacteria.

A group of enzymes which catalyze the hydrolysis of ATP. The hydrolysis reaction is usually coupled with another function such as transporting Ca(2+) across a membrane. These enzymes may be dependent on Ca(2+), Mg(2+), anions, H+, or DNA.

Proteins found in any species of fungus.

Pathologic processes that affect patients after a surgical procedure. They may or may not be related to the disease for which the surgery was done, and they may or may not be direct results of the surgery.

Surgical procedures undertaken to repair abnormal openings through which tissue or parts of organs can protrude or are already protruding.

The reformation of all, or part of, the native conformation of a nucleic acid molecule after the molecule has undergone denaturation.

The region of an enzyme that interacts with its substrate to cause the enzymatic reaction.

A class of enzymes involved in the hydrolysis of the N-glycosidic bond of nitrogen-linked sugars.

An alkylating agent in cancer therapy that may also act as a mutagen by interfering with and causing damage to DNA.

The complex series of phenomena, occurring between the end of one CELL DIVISION and the end of the next, by which cellular material is duplicated and then divided between two daughter cells. The cell cycle includes INTERPHASE, which includes G0 PHASE; G1 PHASE; S PHASE; and G2 PHASE, and CELL DIVISION PHASE.

Virulent bacteriophage and type species of the genus T4-like phages, in the family MYOVIRIDAE. It infects E. coli and is the best known of the T-even phages. Its virion contains linear double-stranded DNA, terminally redundant and circularly permuted.

Operative procedures for the treatment of vascular disorders.

The material of CHROMOSOMES. It is a complex of DNA; HISTONES; and nonhistone proteins (CHROMOSOMAL PROTEINS, NON-HISTONE) found within the nucleus of a cell.

Models used experimentally or theoretically to study molecular shape, electronic properties, or interactions; includes analogous molecules, computer-generated graphics, and mechanical structures.

Minimally invasive procedures, diagnostic or therapeutic, performed within the BLOOD VESSELS. They may be perfomed via ANGIOSCOPY; INTERVENTIONAL MAGNETIC RESONANCE IMAGING; INTERVENTIONAL RADIOGRAPHY; or INTERVENTIONAL ULTRASONOGRAPHY.

The phosphoprotein encoded by the BRCA1 gene (GENE, BRCA1). In normal cells the BRCA1 protein is localized in the nucleus, whereas in the majority of breast cancer cell lines and in malignant pleural effusions from breast cancer patients, it is localized mainly in the cytoplasm. (Science 1995;270(5237):713,789-91)

Lymphocyte progenitor cells that are restricted in their differentiation potential to the B lymphocyte lineage. The pro-B cell stage of B lymphocyte development precedes the pre-B cell stage.

A temperate coliphage, in the genus Mu-like viruses, family MYOVIRIDAE, composed of a linear, double-stranded molecule of DNA, which is able to insert itself randomly at any point on the host chromosome. It frequently causes a mutation by interrupting the continuity of the bacterial OPERON at the site of insertion.

Guanine is a purine nucleobase, one of the four nucleobases in the nucleic acid of DNA and RNA, involved in forming hydrogen bonds between complementary base pairs in double-stranded DNA molecules.

Deletion of sequences of nucleic acids from the genetic material of an individual.

The sequential correspondence of nucleotides in one nucleic acid molecule with those of another nucleic acid molecule. Sequence homology is an indication of the genetic relatedness of different organisms and gene function.

The process by which two molecules of the same chemical composition form a condensation product or polymer.

Enzyme systems composed of two subunits and requiring ATP and magnesium for endonucleolytic activity; they do not function as ATPases. They exist as complexes with modification methylases of similar specificity listed under EC 2.1.1.72 or EC 2.1.1.73. The systems recognize specific short DNA sequences and cleave a short distance, about 24 to 27 bases, away from the recognition sequence to give specific double-stranded fragments with terminal 5'-phosphates. Enzymes from different microorganisms with the same specificity are called isoschizomers. EC 3.1.21.5.

The introduction of a phosphoryl group into a compound through the formation of an ester bond between the compound and a phosphorus moiety.

Gene rearrangement of the B-lymphocyte which results in a substitution in the type of heavy-chain constant region that is expressed. This allows the effector response to change while the antigen binding specificity (variable region) remains the same. The majority of class switching occurs by a DNA recombination event but it also can take place at the level of RNA processing.

Any of the covalently closed DNA molecules found in bacteria, many viruses, mitochondria, plastids, and plasmids. Small, polydisperse circular DNA's have also been observed in a number of eukaryotic organisms and are suggested to have homology with chromosomal DNA and the capacity to be inserted into, and excised from, chromosomal DNA. It is a fragment of DNA formed by a process of looping out and deletion, containing a constant region of the mu heavy chain and the 3'-part of the mu switch region. Circular DNA is a normal product of rearrangement among gene segments encoding the variable regions of immunoglobulin light and heavy chains, as well as the T-cell receptor. (Riger et al., Glossary of Genetics, 5th ed & Segen, Dictionary of Modern Medicine, 1992)

The alignment of CHROMOSOMES at homologous sequences.

The biosynthesis of RNA carried out on a template of DNA. The biosynthesis of DNA from an RNA template is called REVERSE TRANSCRIPTION.

A methyl-directed mismatch DNA REPAIR protein that has weak ATPASE activity. MutS was originally described in ESCHERICHIA COLI.

The insertion of recombinant DNA molecules from prokaryotic and/or eukaryotic sources into a replicating vehicle, such as a plasmid or virus vector, and the introduction of the resultant hybrid molecules into recipient cells without altering the viability of those cells.

Proteins prepared by recombinant DNA technology.

The relationship between the dose of administered radiation and the response of the organism or tissue to the radiation.

Nucleoproteins, which in contrast to HISTONES, are acid insoluble. They are involved in chromosomal functions; e.g. they bind selectively to DNA, stimulate transcription resulting in tissue-specific RNA synthesis and undergo specific changes in response to various hormones or phytomitogens.

The asymmetrical segregation of genes during replication which leads to the production of non-reciprocal recombinant strands and the apparent conversion of one allele into another. Thus, e.g., the meiotic products of an Aa individual may be AAAa or aaaA instead of AAaa, i.e., the A allele has been converted into the a allele or vice versa.

A group of deoxyribonucleotides (up to 12) in which the phosphate residues of each deoxyribonucleotide act as bridges in forming diester linkages between the deoxyribose moieties.

A genotoxicological technique for measuring DNA damage in an individual cell using single-cell gel electrophoresis. Cell DNA fragments assume a "comet with tail" formation on electrophoresis and are detected with an image analysis system. Alkaline assay conditions facilitate sensitive detection of single-strand damage.

Transport proteins that carry specific substances in the blood or across cell membranes.

Proteins found in any species of bacterium.

Genes that code for proteins that regulate the CELL DIVISION CYCLE. These genes form a regulatory network that culminates in the onset of MITOSIS by activating the p34cdc2 protein (PROTEIN P34CDC2).

Reagents with two reactive groups, usually at opposite ends of the molecule, that are capable of reacting with and thereby forming bridges between side chains of amino acids in proteins; the locations of naturally reactive areas within proteins can thereby be identified; may also be used for other macromolecules, like glycoproteins, nucleic acids, or other.

A test used to determine whether or not complementation (compensation in the form of dominance) will occur in a cell with a given mutant phenotype when another mutant genome, encoding the same mutant phenotype, is introduced into that cell.

The products of chemical reactions that result in the addition of extraneous chemical groups to DNA.

A hernia caused by weakness of the anterior ABDOMINAL WALL due to midline defects, previous incisions, or increased intra-abdominal pressure. Ventral hernias include UMBILICAL HERNIA, incisional, epigastric, and spigelian hernias.

The facilitation of a chemical reaction by material (catalyst) that is not consumed by the reaction.

A repeat operation for the same condition in the same patient due to disease progression or recurrence, or as followup to failed previous surgery.

The physiological renewal, repair, or replacement of tissue.

A fractionated cell extract that maintains a biological function. A subcellular fraction isolated by ultracentrifugation or other separation techniques must first be isolated so that a process can be studied free from all of the complex side reactions that occur in a cell. The cell-free system is therefore widely used in cell biology. (From Alberts et al., Molecular Biology of the Cell, 2d ed, p166)

Pairing of purine and pyrimidine bases by HYDROGEN BONDING in double-stranded DNA or RNA.

Viruses whose host is Bacillus. Frequently encountered Bacillus phages include bacteriophage phi 29 and bacteriophage phi 105.

A cell line derived from cultured tumor cells.

Highly reactive chemicals that introduce alkyl radicals into biologically active molecules and thereby prevent their proper functioning. Many are used as antineoplastic agents, but most are very toxic, with carcinogenic, mutagenic, teratogenic, and immunosuppressant actions. They have also been used as components in poison gases.

The degree of similarity between sequences of amino acids. This information is useful for the analyzing genetic relatedness of proteins and species.

Nuclear phosphoprotein encoded by the p53 gene (GENES, P53) whose normal function is to control CELL PROLIFERATION and APOPTOSIS. A mutant or absent p53 protein has been found in LEUKEMIA; OSTEOSARCOMA; LUNG CANCER; and COLORECTAL CANCER.

The repeating structural units of chromatin, each consisting of approximately 200 base pairs of DNA wound around a protein core. This core is composed of the histones H2A, H2B, H3, and H4.

DNA TOPOISOMERASES that catalyze ATP-independent breakage of one of the two strands of DNA, passage of the unbroken strand through the break, and rejoining of the broken strand. DNA Topoisomerases, Type I enzymes reduce the topological stress in the DNA structure by relaxing the superhelical turns and knotted rings in the DNA helix.

A genetic rearrangement through loss of segments of DNA or RNA, bringing sequences which are normally separated into close proximity. This deletion may be detected using cytogenetic techniques and can also be inferred from the phenotype, indicating a deletion at one specific locus.

In vitro method for producing large amounts of specific DNA or RNA fragments of defined length and sequence from small amounts of short oligonucleotide flanking sequences (primers). The essential steps include thermal denaturation of the double-stranded target molecules, annealing of the primers to their complementary sequences, and extension of the annealed primers by enzymatic synthesis with DNA polymerase. The reaction is efficient, specific, and extremely sensitive. Uses for the reaction include disease diagnosis, detection of difficult-to-isolate pathogens, mutation analysis, genetic testing, DNA sequencing, and analyzing evolutionary relationships.

A genus of the family Muridae consisting of eleven species. C. migratorius, the grey or Armenian hamster, and C. griseus, the Chinese hamster, are the two species used in biomedical research.

Structures within the nucleus of fungal cells consisting of or containing DNA, which carry genetic information essential to the cell.

A genus of ascomycetous fungi of the family Schizosaccharomycetaceae, order Schizosaccharomycetales.

An autosomal recessive inherited disorder characterized by choreoathetosis beginning in childhood, progressive CEREBELLAR ATAXIA; TELANGIECTASIS of CONJUNCTIVA and SKIN; DYSARTHRIA; B- and T-cell immunodeficiency, and RADIOSENSITIVITY to IONIZING RADIATION. Affected individuals are prone to recurrent sinobronchopulmonary infections, lymphoreticular neoplasms, and other malignancies. Serum ALPHA-FETOPROTEINS are usually elevated. (Menkes, Textbook of Child Neurology, 5th ed, p688) The gene for this disorder (ATM) encodes a cell cycle checkpoint protein kinase and has been mapped to chromosome 11 (11q22-q23).

Studies used to test etiologic hypotheses in which inferences about an exposure to putative causal factors are derived from data relating to characteristics of persons under study or to events or experiences in their past. The essential feature is that some of the persons under study have the disease or outcome of interest and their characteristics are compared with those of unaffected persons.

Studies in which individuals or populations are followed to assess the outcome of exposures, procedures, or effects of a characteristic, e.g., occurrence of disease.

Derivatives of ACETIC ACID which contain an hydroxy group attached to the methyl carbon.

Endogenous substances, usually proteins, which are effective in the initiation, stimulation, or termination of the genetic transcription process.

A DNA helicase that is a component of TRANSCRIPTION FACTOR TFIIH. It plays an essential role in NUCLEOTIDE EXCISION REPAIR, and mutations in this protein are associated with XERODERMA PIGMENTOSUM.

Enzymes that are part of the restriction-modification systems. They catalyze the endonucleolytic cleavage of DNA sequences which lack the species-specific methylation pattern in the host cell's DNA. Cleavage yields random or specific double-stranded fragments with terminal 5'-phosphates. The function of restriction enzymes is to destroy any foreign DNA that invades the host cell. Most have been studied in bacterial systems, but a few have been found in eukaryotic organisms. They are also used as tools for the systematic dissection and mapping of chromosomes, in the determination of base sequences of DNAs, and have made it possible to splice and recombine genes from one organism into the genome of another. EC 3.21.1.

One of the mechanisms by which CELL DEATH occurs (compare with NECROSIS and AUTOPHAGOCYTOSIS). Apoptosis is the mechanism responsible for the physiological deletion of cells and appears to be intrinsically programmed. It is characterized by distinctive morphologic changes in the nucleus and cytoplasm, chromatin cleavage at regularly spaced sites, and the endonucleolytic cleavage of genomic DNA; (DNA FRAGMENTATION); at internucleosomal sites. This mode of cell death serves as a balance to mitosis in regulating the size of animal tissues and in mediating pathologic processes associated with tumor growth.

An enzyme that transfers methyl groups from O(6)-methylguanine, and other methylated moieties of DNA, to a cysteine residue in itself, thus repairing alkylated DNA in a single-step reaction. EC 2.1.1.63.

Double-stranded nucleic acid molecules (DNA-DNA or DNA-RNA) which contain regions of nucleotide mismatches (non-complementary). In vivo, these heteroduplexes can result from mutation or genetic recombination; in vitro, they are formed by nucleic acid hybridization. Electron microscopic analysis of the resulting heteroduplexes facilitates the mapping of regions of base sequence homology of nucleic acids.

Injuries to the fibrous cords of connective tissue which attach muscles to bones or other structures.

The process of reuniting or replacing broken or worn parts of a denture.

Chemical agents that increase the rate of genetic mutation by interfering with the function of nucleic acids. A clastogen is a specific mutagen that causes breaks in chromosomes.

Proteins and peptides that are involved in SIGNAL TRANSDUCTION within the cell. Included here are peptides and proteins that regulate the activity of TRANSCRIPTION FACTORS and cellular processes in response to signals from CELL SURFACE RECEPTORS. Intracellular signaling peptide and proteins may be part of an enzymatic signaling cascade or act through binding to and modifying the action of other signaling factors.

Surgery which could be postponed or not done at all without danger to the patient. Elective surgery includes procedures to correct non-life-threatening medical problems as well as to alleviate conditions causing psychological stress or other potential risk to patients, e.g., cosmetic or contraceptive surgery.

Macromolecular molds for the synthesis of complementary macromolecules, as in DNA REPLICATION; GENETIC TRANSCRIPTION of DNA to RNA, and GENETIC TRANSLATION of RNA into POLYPEPTIDES.

The span of viability of a cell characterized by the capacity to perform certain functions such as metabolism, growth, reproduction, some form of responsiveness, and adaptability.

An enzyme that catalyzes the reactivation by light of UV-irradiated DNA. It breaks two carbon-carbon bonds in PYRIMIDINE DIMERS in DNA.

A method for determining the sequence specificity of DNA-binding proteins. DNA footprinting utilizes a DNA damaging agent (either a chemical reagent or a nuclease) which cleaves DNA at every base pair. DNA cleavage is inhibited where the ligand binds to DNA. (from Rieger et al., Glossary of Genetics: Classical and Molecular, 5th ed)

Nuclear antigen with a role in DNA synthesis, DNA repair, and cell cycle progression. PCNA is required for the coordinated synthesis of both leading and lagging strands at the replication fork during DNA replication. PCNA expression correlates with the proliferation activity of several malignant and non-malignant cell types.

The characteristic 3-dimensional shape of a protein, including the secondary, supersecondary (motifs), tertiary (domains) and quaternary structure of the peptide chain. PROTEIN STRUCTURE, QUATERNARY describes the conformation assumed by multimeric proteins (aggregates of more than one polypeptide chain).

An enzyme which catalyzes an endonucleolytic cleavage near PYRIMIDINE DIMERS to produce a 5'-phosphate product. The enzyme acts on the damaged DNA strand, from the 5' side of the damaged site.

Phase of the CELL CYCLE following G1 and preceding G2 when the entire DNA content of the nucleus is replicated. It is achieved by bidirectional replication at multiple sites along each chromosome.

The intracellular transfer of information (biological activation/inhibition) through a signal pathway. In each signal transduction system, an activation/inhibition signal from a biologically active molecule (hormone, neurotransmitter) is mediated via the coupling of a receptor/enzyme to a second messenger system or to an ion channel. Signal transduction plays an important role in activating cellular functions, cell differentiation, and cell proliferation. Examples of signal transduction systems are the GAMMA-AMINOBUTYRIC ACID-postsynaptic receptor-calcium ion channel system, the receptor-mediated T-cell activation pathway, and the receptor-mediated activation of phospholipases. Those coupled to membrane depolarization or intracellular release of calcium include the receptor-mediated activation of cytotoxic functions in granulocytes and the synaptic potentiation of protein kinase activation. Some signal transduction pathways may be part of larger signal transduction pathways; for example, protein kinase activation is part of the platelet activation signal pathway.

An enzyme that catalyzes the HYDROLYSIS of the N-glycosidic bond between sugar phosphate backbone and URACIL residue during DNA synthesis.

Use of restriction endonucleases to analyze and generate a physical map of genomes, genes, or other segments of DNA.

Process of generating a genetic MUTATION. It may occur spontaneously or be induced by MUTAGENS.

An abnormal balloon- or sac-like dilatation in the wall of AORTA.

A combination of congenital heart defects consisting of four key features including VENTRICULAR SEPTAL DEFECTS; PULMONARY STENOSIS; RIGHT VENTRICULAR HYPERTROPHY; and a dextro-positioned AORTA. In this condition, blood from both ventricles (oxygen-rich and oxygen-poor) is pumped into the body often causing CYANOSIS.

The ordered rearrangement of gene regions by DNA recombination such as that which occurs normally during development.

The steps that generate the 3' ends of mature RNA molecules. For most mRNAs (RNA, MESSENGER), 3' end processing referred to as POLYADENYLATION includes the addition of POLY A.

Devices that provide support for tubular structures that are being anastomosed or for body cavities during skin grafting.

A 60-kDa extracellular protein of Streptomyces avidinii with four high-affinity biotin binding sites. Unlike AVIDIN, streptavidin has a near neutral isoelectric point and is free of carbohydrate side chains.

Identification of proteins or peptides that have been electrophoretically separated by blot transferring from the electrophoresis gel to strips of nitrocellulose paper, followed by labeling with antibody probes.