Bacteriophage mu. Medical search

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.

Viruses whose hosts are bacterial cells.

Viruses whose host is Escherichia coli.

The phenomenon by which a temperate phage incorporates itself into the DNA of a bacterial host, establishing a kind of symbiotic relation between PROPHAGE and bacterium which results in the perpetuation of the prophage in all the descendants of the bacterium. Upon induction (VIRUS ACTIVATION) by various agents, such as ultraviolet radiation, the phage is released, which then becomes virulent and lyses the bacterium.

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.

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.

Deoxyribonucleic acid that makes up the genetic material of viruses.

A temperate inducible phage and type species of the genus lambda-like viruses, in the family SIPHOVIRIDAE. Its natural host is E. coli K12. Its VIRION contains linear double-stranded DNA with single-stranded 12-base 5' sticky ends. The DNA circularizes on infection.

Proteins found in any species of virus.

Virulent bacteriophage and type species of the genus T7-like phages, in the family PODOVIRIDAE, that infects E. coli. It consists of linear double-stranded DNA, terminally redundant, and non-permuted.

The functional hereditary units of VIRUSES.

Bacterial proteins that are used by BACTERIOPHAGES to incorporate their DNA into the DNA of the "host" bacteria. They are DNA-binding proteins that function in genetic recombination as well as in transcriptional and translational regulation.

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.

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

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 series of 7 virulent phages which infect E. coli. The T-even phages T2, T4; (BACTERIOPHAGE T4), and T6, and the phage T5 are called "autonomously virulent" because they cause cessation of all bacterial metabolism on infection. Phages T1, T3; (BACTERIOPHAGE T3), and T7; (BACTERIOPHAGE T7) are called "dependent virulent" because they depend on continued bacterial metabolism during the lytic cycle. The T-even phages contain 5-hydroxymethylcytosine in place of ordinary cytosine in their DNA.

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.

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.

Discrete segments of DNA which can excise and reintegrate to another site in the genome. Most are inactive, i.e., have not been found to exist outside the integrated state. DNA transposable elements include bacterial IS (insertion sequence) elements, Tn elements, the maize controlling elements Ac and Ds, Drosophila P, gypsy, and pogo elements, the human Tigger elements and the Tc and mariner elements which are found throughout the animal kingdom.

Virulent bacteriophage and sole member of the genus Cystovirus that infects Pseudomonas species. The virion has a segmented genome consisting of three pieces of doubled-stranded DNA and also a unique lipid-containing envelope.

A plasmid whose presence in the cell, either extrachromosomal or integrated into the BACTERIAL CHROMOSOME, determines the "sex" of the bacterium, host chromosome mobilization, transfer via conjugation (CONJUGATION, GENETIC) of genetic material, and the formation of SEX PILI.

In bacteria, a group of metabolically related genes, with a common promoter, whose transcription into a single polycistronic MESSENGER RNA is under the control of an OPERATOR REGION.

The type species of the genus MICROVIRUS. A prototype of the small virulent DNA coliphages, it is composed of a single strand of supercoiled circular DNA, which on infection, is converted to a double-stranded replicative form by a host enzyme.

A broad category of viral proteins that play indirect roles in the biological processes and activities of viruses. Included here are proteins that either regulate the expression of viral genes or are involved in modifying host cell functions. Many of the proteins in this category serve multiple functions.

A species of temperate bacteriophage in the genus P2-like viruses, family MYOVIRIDAE, which infects E. coli. It consists of linear double-stranded DNA with 19-base sticky ends.

The process by which a DNA molecule is duplicated.

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.

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

Temperate bacteriophage of the genus INOVIRUS which infects enterobacteria, especially E. coli. It is a filamentous phage consisting of single-stranded DNA and is circularly permuted.

Viruses whose nucleic acid is DNA.

An ATP-dependent protease found in prokaryotes, CHLOROPLASTS, and MITOCHONDRIA. It is a soluble multisubunit complex that plays a role in the degradation of many abnormal proteins.

Bacteriophage in the genus T7-like phages, of the family PODOVIRIDAE, which is very closely related to BACTERIOPHAGE T7.

Any method used for determining the location of and relative distances between genes on a chromosome.

A technique of bacterial typing which differentiates between bacteria or strains of bacteria by their susceptibility to one or more bacteriophages.

A species of temperate bacteriophage in the genus P1-like viruses, family MYOVIRIDAE, which infects E. coli. It is the largest of the COLIPHAGES and consists of double-stranded DNA, terminally redundant, and circularly permuted.

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.

A category of nucleic acid sequences that function as units of heredity and which code for the basic instructions for the development, reproduction, and maintenance of organisms.

The transfer of bacterial DNA by phages from an infected bacterium to another bacterium. This also refers to the transfer of genes into eukaryotic cells by viruses. This naturally occurring process is routinely employed as a GENE TRANSFER TECHNIQUE.

The process of intracellular viral multiplication, consisting of the synthesis of PROTEINS; NUCLEIC ACIDS; and sometimes LIPIDS, and their assembly into a new infectious particle.

Viruses whose host is Salmonella. A frequently encountered Salmonella phage is BACTERIOPHAGE P22.

A family of BACTERIOPHAGES and ARCHAEAL VIRUSES which are characterized by long, non-contractile tails.

A class of enzymes that transfers nucleotidyl residues. EC 2.7.7.

Enzymes that catalyze DNA template-directed extension of the 3'-end of an RNA strand one nucleotide at a time. They can initiate a chain de novo. In eukaryotes, three forms of the enzyme have been distinguished on the basis of sensitivity to alpha-amanitin, and the type of RNA synthesized. (From Enzyme Nomenclature, 1992).

The functional hereditary units of BACTERIA.

Proteins found in any species of bacterium.

Deoxyribonucleic acid that makes up the genetic material of bacteria.

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.

A highly abundant DNA binding protein whose expression is strongly correlated with the growth phase of bacteria. The protein plays a role in regulating DNA topology and activation of RIBOSOMAL RNA transcription. It was originally identified as a factor required for inversion stimulation by the Hin recombinase of SALMONELLA and Gin site-specific recombinase of BACTERIOPHAGE MU.

Bacteriophages whose genetic material is RNA, which is single-stranded in all except the Pseudomonas phage phi 6 (BACTERIOPHAGE PHI 6). All RNA phages infect their host bacteria via the host's surface pili. Some frequently encountered RNA phages are: BF23, F2, R17, fr, PhiCb5, PhiCb12r, PhiCb8r, PhiCb23r, 7s, PP7, Q beta phage, MS2 phage, and BACTERIOPHAGE PHI 6.

Rupture of bacterial cells due to mechanical force, chemical action, or the lytic growth of BACTERIOPHAGES.

Bacteriophage and type species in the genus Tectivirus, family TECTIVIRIDAE. They are specific for Gram-negative bacteria.

Viruses whose host is Pseudomonas. A frequently encountered Pseudomonas phage is BACTERIOPHAGE PHI 6.

Viruses whose host is Staphylococcus.

Biologically active DNA which has been formed by the in vitro joining of segments of DNA from different sources. It includes the recombination joint or edge of a heteroduplex region where two recombining DNA molecules are connected.

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

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

A family of bacteriophages which are characterized by short, non-contractile tails.

A class of opioid receptors recognized by its pharmacological profile. Mu opioid receptors bind, in decreasing order of affinity, endorphins, dynorphins, met-enkephalin, and leu-enkephalin. They have also been shown to be molecular receptors for morphine.

Viruses whose host is Streptococcus.

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.

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

Proteins which maintain the transcriptional quiescence of specific GENES or OPERONS. Classical repressor proteins are DNA-binding proteins that are normally bound to the OPERATOR REGION of an operon, or the ENHANCER SEQUENCES of a gene until a signal occurs that causes their release.

Proteins obtained from 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.

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

A parasexual process in BACTERIA; ALGAE; FUNGI; and ciliate EUKARYOTA for achieving exchange of chromosome material during fusion of two cells. In bacteria, this is a uni-directional transfer of genetic material; in protozoa it is a bi-directional exchange. In algae and fungi, it is a form of sexual reproduction, with the union of male and female gametes.

DNA sequences which are recognized (directly or indirectly) and bound by a DNA-dependent RNA polymerase during the initiation of transcription. Highly conserved sequences within the promoter include the Pribnow box in bacteria and the TATA BOX in eukaryotes.

Proteins found in the tail sections of DNA and RNA viruses. It is believed that these proteins play a role in directing chain folding and assembly of polypeptide chains.

The complete genetic complement contained in a DNA or RNA molecule in a virus.

A bacteriophage genus of the family LEVIVIRIDAE, whose viruses contain the short version of the genome and have a separate gene for cell lysis.

Any of the processes by which cytoplasmic factors influence the differential control of gene action in viruses.

The sum of the weight of all the atoms in a molecule.

The adhesion of gases, liquids, or dissolved solids onto a surface. It includes adsorptive phenomena of bacteria and viruses onto surfaces as well. ABSORPTION into the substance may follow but not necessarily.

The folding of an organism's DNA molecule into a compact, orderly structure that fits within the limited space of a CELL or VIRUS PARTICLE.

An efficient DNA sequencing strategy based on the bacteriophage mu in vitro DNA transposition reaction. (1/284)

A highly efficient DNA sequencing strategy was developed on the basis of the bacteriophage Mu in vitro DNA transposition reaction. In the reaction, an artificial transposon with a chloramphenicol acetyltransferase (cat) gene as a selectable marker integrated into the target plasmid DNA containing a 10.3-kb mouse genomic insert to be sequenced. Bacterial clones carrying plasmids with the transposon insertions in different positions were produced by transforming transposition reaction products into Escherichia coli cells that were then selected on appropriate selection plates. Plasmids from individual clones were isolated and used as templates for DNA sequencing, each with two primers specific for the transposon sequence but reading the sequence into opposite directions, thus creating a minicontig. By combining the information from overlapping minicontigs, the sequence of the entire 10,288-bp region of mouse genome including six exons of mouse Kcc2 gene was obtained. The results indicated that the described methodology is extremely well suited for DNA sequencing projects in which considerable sequence information is on demand. In addition, massive DNA sequencing projects, including those of full genomes, are expected to benefit substantially from the Mu strategy. (+info)

SmpB, a unique RNA-binding protein essential for the peptide-tagging activity of SsrA (tmRNA). (2/284)

In bacteria, SsrA RNA recognizes ribosomes stalled on defective messages and acts as a tRNA and mRNA to mediate the addition of a short peptide tag to the C-terminus of the partially synthesized nascent polypeptide chain. The SsrA-tagged protein is then degraded by C-terminal-specific proteases. SmpB, a unique RNA-binding protein that is conserved throughout the bacterial kingdom, is shown here to be an essential component of the SsrA quality-control system. Deletion of the smpB gene in Escherichia coli results in the same phenotypes observed in ssrA-defective cells, including a variety of phage development defects and the failure to tag proteins translated from defective mRNAs. Purified SmpB binds specifically and with high affinity to SsrA RNA and is required for stable association of SsrA with ribosomes in vivo. Formation of an SmpB-SsrA complex appears to be critical in mediating SsrA activity after aminoacylation with alanine but prior to the transpeptidation reaction that couples this alanine to the nascent chain. SsrA RNA is present at wild-type levels in the smpB mutant arguing against a model of SsrA action that involves direct competition for transcription factors. (+info)

Criss-crossed interactions between the enhancer and the att sites of phage Mu during DNA transposition. (3/284)

A bipartite enhancer sequence (composed of the O1 and O2 operator sites) is essential for assembly of the functional tetramer of phage Mu transposase (MuA) on supercoiled DNA substrates. A three-site interaction (LER) between the left (L) and right (R) ends of Mu (att sites) and the enhancer (E) precedes tetramer assembly. We have dissected the role of the enhancer in tetramer assembly by using two transposase proteins that have a common att site specificity, but are distinct in their enhancer specificity. The activity of these proteins on substrates containing hybrid enhancers reveals a 'criss-crossed' pattern of interaction between att and enhancer sites. The left operator, O1, of the enhancer interacts specifically with the transposase subunit at the R1 site (within the right att sequence) that is responsible for cleaving the left end of Mu. The right operator, O2, shows a preferential interaction with the transposase subunit at the L1 site (within the left att sequence) that is responsible for cleaving the right end of Mu. (+info)

Natural synthesis of a DNA-binding protein from the C-terminal domain of DNA gyrase A in Borrelia burgdorferi. (4/284)

We have identified a 34 kDa DNA-binding protein with an HU-like activity in the Lyme disease spirochete Borrelia burgdorferi. The 34 kDa protein is translated from an abundant transcript initiated within the gene encoding the A subunit of DNA gyrase. Translation of the 34 kDa protein starts at residue 499 of GyrA and proceeds in the same reading frame as full-length GyrA, resulting in an N-terminal-truncated protein. The 34 kDa GyrA C-terminal domain, although not homologous, substitutes for HU in the formation of the Type 1 complex in Mu transposition, and complements an HU-deficient strain of Escherichia coli. This is the first example of constitutive expression of two gene products in the same open reading frame from a single gene in a prokaryotic cellular system. (+info)

Replacement of the bacteriophage Mu strong gyrase site and effect on Mu DNA replication. (5/284)

The bacteriophage Mu strong gyrase site (SGS) is required for efficient replicative transposition and functions by promoting the synapsis of prophage termini. To look for other sites which could substitute for the SGS in promoting Mu replication, we have replaced the SGS in the middle of the Mu genome with fragments of DNA from various sources. A central fragment from the transposing virus D108 allowed efficient Mu replication and was shown to contain a strong gyrase site. However, neither the strong gyrase site from the plasmid pSC101 nor the major gyrase site from pBR322 could promote efficient Mu replication, even though the pSC101 site is a stronger gyrase site than the Mu SGS as assayed by cleavage in the presence of gyrase and the quinolone enoxacin. To look for SGS-like sites in the Escherichia coli chromosome which might be involved in organizing nucleoid structure, fragments of E. coli chromosomal DNA were substituted for the SGS: first, repeat sequences associated with gyrase binding (bacterial interspersed mosaic elements), and, second, random fragments of the entire chromosome. No fragments were found that could replace the SGS in promoting efficient Mu replication. These results demonstrate that the gyrase sites from the transposing phages possess unusual properties and emphasize the need to determine the basis of these properties. (+info)

Organization and dynamics of the Mu transpososome: recombination by communication between two active sites. (6/284)

Movement of transposable genetic elements requires the cleavage of each end of the element genome and the subsequent joining of these cleaved ends to a new target DNA site. During Mu transposition, these reactions are catalyzed by a tetramer of four identical transposase subunits bound to the paired Mu DNA ends. To elucidate the organization of active sites within this tetramer, the subunit providing the essential active site DDE residues for each cleavage and joining reaction was determined. We demonstrate that recombination of the two Mu DNA ends is catalyzed by two active sites, where one active site promotes both cleavage and joining of one Mu DNA end. This active site uses all three DDE residues from the subunit bound to the transposase binding site proximal to the cleavage site on the other Mu DNA end (catalysis in trans). In addition, we uncover evidence that the catalytic activity of these two active sites is coupled such that the coordinated joining of both Mu DNA ends is favored during recombination. On the basis of these results, we propose that the DNA joining stage requires a cooperative transition within the transposase-DNA complex. The cooperative utilization of active sites supplied in trans by Mu transposase provides an example of how mobile elements can ensure concomitant recombination of distant DNA sites. (+info)

Identification of SoxS-regulated genes in Salmonella enterica serovar typhimurium. (7/284)

Salmonella enterica serovar Typhimurium responds to superoxide-generating agents through soxR-mediated activation of the soxS gene, whose product, SoxS, is necessary for resistance to oxidative stress. The S. enterica serovar Typhimurium soxRS system also mediates redox-inducible resistance to diverse antibiotics, which may be relevant to clinical infections. In order to identify SoxS-regulated genes in S. enterica serovar Typhimurium, a lacI-regulated expression system for the S. enterica serovar Typhimurium soxS gene was developed. This system was used to demonstrate that soxS expression is sufficient for the induction of resistance to the superoxide-generating drug paraquat and for the transcriptional activation of the sodA and micF genes. In addition, a library of random lacZ insertions was generated and screened for clones displaying differential beta-galactosidase activity in the presence or absence of SoxS. This selection yielded six independent chromosomal lacZ transcriptional fusions that were activated by either artificial expression of SoxS or exposure of wild-type cells to micromolar concentrations of paraquat. Moreover, disruption of the inducible genes by the insertions rendered S. enterica serovar Typhimurium hypersensitive to millimolar concentrations of paraquat. Nucleotide sequence determination identified the disrupted genes as sodA (Mn-containing superoxide dismutase), fpr (NADPH:ferredoxin oxidoreductase), and ydbK (a putative Fe-S-containing reductase). (+info)

Mu DNA reintegration upon excision: evidence for a possible involvement of nucleoid folding. (8/284)

Mutations induced by the integration of a Mugem2ts prophage can revert at frequencies around 1x10(-6). In these revertant clones, the prophage excised from its original localization is not lost but reintegrated elsewhere in the host genome. One of the most intriguing aspects of this process is that the prophage reintegration is not randomly distributed: there is a strong correlation between the original site of insertion (the donor site) and the target site of the phage DNA migration (the receptor site). In this paper, it is shown that in the excision-reintegration process mediated by Mugem2ts, the position of the initial prophage site strongly influences the location of the reintegration site. In addition, for each donor site, the receptor site is a discrete DNA region within which the excised Mu DNA can reintegrate and the two sites implicated in phage DNA migration must be located on the same DNA molecule. These data suggest the involvement of nucleoid folding in the excision-reintegration process. (+info)