Disease relevance of umuC

• Angelicin- plus near-UV-induced mutations were umuC dependent in Escherichia coli K-12 [1].
• The induction of umuC gene expression, cell lethality, induction of W-reactivation of UV-irradiated lambda-phage and the induction of mutagenesis caused by bleomycin (Blm) were studied in Escherichia coli K-12 strains with special references to the effects of SOS repair deficiencies [2].
• The umuD and umuC genes were placed under the control of a regulated phage lambda PL promoter and a synthetic ribosome-binding site, and the distance to the UmuD start was adjusted to maximize gene expression [3].
• Clomid caused DNA-strand breaks, but few SOS responses such as mutation, induction of prophage and expression of the umuC+ gene were induced [4].
• To examine the mutagenic potential of these agents, a genotoxicity assay was employed using Salmonella typhimurium NM2009, a bacterial strain expressing the umuC SOS response gene fused to a beta-galactosidase reporter lacZ gene [5].

High impact information on umuC

• Homologs of the umuC gene were found on native conjugative plasmids, which often carry multiple antibiotic-resistant genes [6].
• To initiate a biochemical characterization of the role of these proteins, we have developed a plasmid system that gives efficient expression of the umuD and umuC genes [3].
• The product of the umuC gene is required for UV and chemical mutagenesis in Escherichia coli [7].
• By the use of the Mud(Ap, lac) bacteriophage, we have obtained an operon fusion of the lac structural genes to the promoter/regulatory region of the umuC gene [7].
• Further, we found that a significant fraction of potentially lethal thymine glycols could be ultraviolet-reactivated in an umuC lexA recA-independent manner, suggesting the existence of an as yet uncharacterized damage-inducible SOS-independent mode of thymine glycol repair [8].

Chemical compound and disease context of umuC

• Escherichia coli umuC122::Tn 5 was mutagenized with N-methyl-N'-nitro-N-nitrosoguanidine to isolate mutations that block the residual gamma-radiation mutagenesis observed in umuC strains [9].
• Effects of vanillin on UV killing of umuC mutant strains of E. coli were investigated in order to analyze the antimutagenic role of vanillin in mutagenesis [10].
• In studies of mutagenesis induced by the carcinogen N-ethyl-N-nitrosourea (ENU) in the bacterium Escherichia coli FX-11, it was observed that G:C to A:T transitions did not require the inducible umuDC gene products, while a portion of the A:T to G:C transitions and all transversion mutations were dependent on a functional umuC gene [11].
• Effect of deficiency in excision repair and umuC function on the mutagenicity with ethylene oxide in the lacI gene of E. coli [12].
• The products of the uvrA and uvrB genes are required for the excision repair of pyrimidine dimers and other bulky lesions; the umuC gene product is required for most chemical mutagenesis in E. coli [13].

Biological context of umuC

• UV mutations produced in this cell-free reaction required the recA and umuC gene products and were prevented by rifampicin, an inhibitor of RNA polymerase, which inhibited plasmid replication [14].
• The reading frames of umuD and umuC overlap by 1 base pair, and the reading frames of mucA and mucB overlap by 13 base pairs [15].
• The umuC mutation, which drastically reduced spontaneous mutagensis, had no effect on genetic recombination [16].
• The umuC mutants are defective in mutagenesis and slightly sensitive to DNA damaging agents [17].
• The two genes comprise an operon, and the transcriptional direction is from umuD to umuC [17].

Associations of umuC with chemical compounds

• In fact expression of the umuC gene was induced by lower concentrations of MNNG in the presence of o-vanillin [18].
• In addition, we found that photoreactivation of cyclobutane pyrimidine dimers reversed umuC induction to the same extent as it reversed mutagenesis [19].
• The inducing activity of quercetin is higher for sfiA than for recA and umuC genes in the absence of S9 mix [20].
• Further experiments indicated that chloroquine-induced reversion frequencies were essentially identical in wild-type, recA, umuC and uvrC derivatives of DG1669, as well as in strains carrying the mutation enhancing plasmid pKM101, over a wide range of doses (0-1200 micrograms/plate) [21].
• Introduction of a umuC::Tn5 mutation into a strain carrying the lacZ19136 marker resulted in enhanced reversion by 9-aminoacridine and the acridine half-mustard ICR191, whereas reversion of the lacZ19124 marker was decreased (but not abolished) in a umuC strain [22].

Regulatory relationships of umuC

• (1) The umuC gene is inducible by Blm and the induction is regulated by the lexA and recA genes [2].
• The umuC gene fusion was induced at lower concentrations of 4-quinolone than was the sfiA gene fusion [23].
• The plasmid pSK1002 bears an umuC::lacZ fusion in which lacZ is under the control of the umuC promoter and regulated under the SOS regulon [24].

Other interactions of umuC

• From these and the previous results of genetic and biochemical studies on the cloned genes, we conclude that the former is the umuD and the latter is the umuC gene [25].
• We found the following sequence: fabD purB atte14 umuC [26].
• The mutants can be classified into three groups by the location of the mutations, umuA, umuB and umuC [27].
• A small fraction of the recF recB-independent repair of DSG is dependent upon the umuC gene, and may define an error-prone pathway of postreplication repair [28].
• Crosslink repair in uvrA bacteria is reduced but not eliminated by a mutation in the umuC gene [29].

Analytical, diagnostic and therapeutic context of umuC

• Further subcloning, Tn1000 insertion inactivation, and complementation tests revealed that there are two genes, umuD and umuC in the former umuC region [17].
• Mutational spectrum analysis of umuC-independent and umuC-dependent gamma-radiation mutagenesis in Escherichia coli [30].
• With DNA probes to the E. coli umuD and umuC genes, we detected, by Southern blot hybridization, sequences similar to both of these genes in S. typhimurium LT2 [31].

References