Disease relevance of ssb

• Signal strains that can detect certain DNA replication and membrane mutants of Escherichia coli: isolation of a new ssb allele, ssb-3 [1].
• As is true in ssb+ strains tif-1 (recA441) was found to allow thermal induction of prophage lambda + and Weigle reactivation in ssb-1 and ssb-113 strains [2].
• Isolation of Brucella abortus ssb and uvrA genes from a genomic library by use of lymphocytes as probes [3].
• In bacteriophages T1 and T4, local decay effects were compared with effects of the emitted electrons by induction of both single (ssb) and double strand breaks (dsb) in the intact phage head and in extended free state DNA [4].
• To study the biochemical properties of SSB's from Deinococcus grandis (DgrSSB) and Deinococcus proteolyticus (DprSSB), we have cloned the ssb genes obtained by PCR and have developed Escherichia coli overexpression systems [5].

High impact information on ssb

• On the chromosome, the ssb gene is located adjacent to the excision repair gene uvrA, but the two genes are transcribed in opposite directions. uvrA has been shown to be part of the E. coli SOS system by introducing Mud(Ap, lac) insertions distal to the regulatory region of the gene in the chromosome [6].
• Therefore, we used plasmids harbouring the regulatory region of ssb fused to the galK structural gene, while leaving an intact ssb gene in the chromosome [6].
• The coding region of ssb is 534 base pairs and is preceeded and followed by dyad symmetries of 39 base pairs and 27 base pairs, respectively [7].
• Non-aromatic amino acid substitutions for SSB Trp-54 (ssb W54-->L and ssb W54-->S) produced the greatest effects on in vivo protein function including altered marker linkage subsequent to generalized transduction, extreme UV sensitivity, and a lack of ability to support SOS induction [8].
• The binding inhibited in vitro expression of ssb and bla but not nusA [9].

Biological context of ssb

• Furthermore, it appears that the presence of the ssb gene on a multicopy plasmid sensitizes wild-type cells to UV light [10].
• By localized mutagenesis of the 92-min region of the chromosome of the sulA::lac signal strain and picking blue colonies, we isolated a novel ssb allele that confers the same extreme UV sensitivity as a delta recA allele, which is a considerably greater sensitivity than that conferred by the two well-studied ssb alleles, ssb-1 and ssb-113 [1].
• The phenotypes of these ssb mutants indicated that they were largely unaffected in other functions mediated by SSB, such as DNA replication, recombination, and repair [11].
• Identification and characterization of ssb and uup mutants with increased frequency of precise excision of transposon Tn10 derivatives: nucleotide sequence of uup in Escherichia coli [11].
• A cosmid (pND320) bearing 42.5 kb of Escherichia coli chromosomal DNA, including the genes between xylE and ssb near minute 92 on the linkage map, was isolated by selection for complementation of a dnaB mutation [12].

Associations of ssb with chemical compounds

• These ssb strains exhibited varying sensitivities to ultraviolet irradiation and methylmethane sulfonate that correlated with the rate of constitutive synthesis of SOS proteins, spontaneous commitment to virulent growth of lambda lysogens, and elevation of endogenous mutation rates [13].

Regulatory relationships of ssb

• We reported earlier that the SOS box of the neighbouring uvrA gene also controls the transcription of the ssb gene [14].

Other interactions of ssb

• Effect of lexA and ssb genes, present on a uvrA recombinant plasmid, on the UV survival of Escherichia coli K-12 [10].
• Three ssb mutants were analyzed under parallel physiological conditions for the induction of SOS proteins (products of recA, uvrA, and an unknown gene), the production of mutants, the induction of lambda prophage, and sensitivity to DNA damaging agents [13].
• Their mutation mapped between the ssb and melA genes at 92 min on the genome, at a site recently designated fdhF by Pecher et al [15].
• The activity of dnaA, dnaZ, and ssb gene products were 200-, 90-, and 60-fold greater, respectively, in the cells containing these plasmids than in normal cells [16].
• A bac mutant of bacteriophage P1 that suppresses the temperature sensitivity of dnaB mutants does not affect the phenotype of lexC or ssbA mutants [17].

References