Telomere
Telomere Homeostasis
Maintenance of TELOMERE length. During DNA REPLICATION, chromosome ends loose some of their telomere sequence (TELOMERE SHORTENING.) Various cellular mechanism are involved in repairing, extending, and recapping the telomere ends.
Telomerase
An essential ribonucleoprotein reverse transcriptase that adds telomeric DNA to the ends of eukaryotic CHROMOSOMES.
Telomere-Binding Proteins
Telomeric Repeat Binding Protein 1
A ubiquitously expressed telomere-binding protein that is present at TELOMERES throughout the CELL CYCLE. It is a suppressor of telomere elongation and may be involved in stabilization of telomere length. It is structurally different from TELOMERIC REPEAT BINDING PROTEIN 2 in that it contains acidic N-terminal amino acid residues.
Telomeric Repeat Binding Protein 2
A ubiquitously expressed telomere-binding protein that is present at TELOMERES throughout the cell cycle. It is a suppressor of telomere elongation and may be involved in stabilization of telomere length. It is structurally different from TELOMERIC REPEAT BINDING PROTEIN 1 in that it contains basic N-terminal amino acid residues.
Cell Aging
In Situ Hybridization, Fluorescence
Dyskeratosis Congenita
A predominantly X-linked recessive syndrome characterized by a triad of reticular skin pigmentation, nail dystrophy and leukoplakia of mucous membranes. Oral and dental abnormalities may also be present. Complications are a predisposition to malignancy and bone marrow involvement with pancytopenia. (from Int J Paediatr Dent 2000 Dec;10(4):328-34) The X-linked form is also known as Zinsser-Cole-Engman syndrome and involves the gene which encodes a highly conserved protein called dyskerin.
Tankyrases
G-Quadruplexes
Higher-order DNA and RNA structures formed from guanine-rich sequences. They are formed around a core of at least 2 stacked tetrads of hydrogen-bonded GUANINE bases. They can be formed from one two or four separate strands of DNA (or RNA) and can display a wide variety of topologies, which are a consequence of various combinations of strand direction, length, and sequence. (From Nucleic Acids Res. 2006;34(19):5402-15)
Chromosomal Instability
An increased tendency to acquire CHROMOSOME ABERRATIONS when various processes involved in chromosome replication, repair, or segregation are dysfunctional.
Chromosomes, Fungal
Structures within the nucleus of fungal cells consisting of or containing DNA, which carry genetic information essential to the cell.
Leukocytes
White blood cells. These include granular leukocytes (BASOPHILS; EOSINOPHILS; and NEUTROPHILS) as well as non-granular leukocytes (LYMPHOCYTES and MONOCYTES).
DNA-Binding Proteins
Repetitive Sequences, Nucleic Acid
Sequences of DNA or RNA that occur in multiple copies. There are several types: INTERSPERSED REPETITIVE SEQUENCES are copies of transposable elements (DNA TRANSPOSABLE ELEMENTS or RETROELEMENTS) dispersed throughout the genome. TERMINAL REPEAT SEQUENCES flank both ends of another sequence, for example, the long terminal repeats (LTRs) on RETROVIRUSES. Variations may be direct repeats, those occurring in the same direction, or inverted repeats, those opposite to each other in direction. TANDEM REPEAT SEQUENCES are copies which lie adjacent to each other, direct or inverted (INVERTED REPEAT SEQUENCES).
Saccharomyces cerevisiae Proteins
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.
Saccharomyces cerevisiae
DNA Damage
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.
Genomic Instability
Mutation
Chromosomes
In a prokaryotic cell or in the nucleus of a eukaryotic cell, a structure consisting of or containing DNA which carries the genetic information essential to the cell. (From Singleton & Sainsbury, Dictionary of Microbiology and Molecular Biology, 2d ed)
Aging
RNA
A polynucleotide consisting essentially of chains with a repeating backbone of phosphate and ribose units to which nitrogenous bases are attached. RNA is unique among biological macromolecules in that it can encode genetic information, serve as an abundant structural component of cells, and also possesses catalytic activity. (Rieger et al., Glossary of Genetics: Classical and Molecular, 5th ed)
Euplotes
Blotting, Southern
A method (first developed by E.M. Southern) for detection of DNA that has been electrophoretically separated and immobilized by blotting on nitrocellulose or other type of paper or nylon membrane followed by hybridization with labeled NUCLEIC ACID PROBES.
DNA
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).
Silent Information Regulator Proteins, Saccharomyces cerevisiae
A set of nuclear proteins in SACCHAROMYCES CEREVISIAE that are required for the transcriptional repression of the silent mating type loci. They mediate the formation of silenced CHROMATIN and repress both transcription and recombination at other loci as well. They are comprised of 4 non-homologous, interacting proteins, Sir1p, Sir2p, Sir3p, and Sir4p. Sir2p, an NAD-dependent HISTONE DEACETYLASE, is the founding member of the family of SIRTUINS.
Base Sequence
Exodeoxyribonucleases
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.
Chromosomes, Human
Very long DNA molecules and associated proteins, HISTONES, and non-histone chromosomal proteins (CHROMOSOMAL PROTEINS, NON-HISTONE). Normally 46 chromosomes, including two sex chromosomes are found in the nucleus of human cells. They carry the hereditary information of the individual.
Chromosome Aberrations
Abnormal number or structure of chromosomes. Chromosome aberrations may result in CHROMOSOME DISORDERS.
Recombination, Genetic
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.
Aging, Premature
DNA Replication
The process by which a DNA molecule is duplicated.
Molecular Sequence Data
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.
Cell Cycle Proteins
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.
Rad52 DNA Repair and Recombination Protein
A DNA-binding protein that mediates DNA REPAIR of double strand breaks, and HOMOLOGOUS RECOMBINATION.
DNA Repair
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.
RecQ Helicases
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.