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RecA Protein (reca + protein)
Selected AbstractsFunctional overlap between RecA and MgsA (RarA) in the rescue of stalled replication forks in Escherichia coliGENES TO CELLS, Issue 3 2005Tatsuya Shibata Escherichia coli RecA protein plays a role in DNA homologous recombination, recombination repair, and the rescue of stalled or collapsed replication forks. The mgsA (rarA) gene encodes a highly conserved DNA-dependent ATPase, whose yeast orthologue, MGS1, plays a role in maintaining genomic stability. In this study, we show a functional relationship between mgsA and recA during DNA replication. The mgsA recA double mutant grows more slowly and has lower viability than a recA single mutant, but they are equally sensitive to UV-induced DNA damage. Mutations in mgsA and recA cause lethality in DNA polymerase I deficient cells, and suppress the temperature-dependent growth defect of dnaE486 (Pol III ,-catalytic subunit). Moreover, recAS25P, a novel recA allele identified in this work, does not complement the slow growth of ,mgsA ,recA cells or the lethality of polA12 ,recA, but is proficient in DNA repair, homologous recombination, SOS mutagenesis and SOS induction. These results suggest that RecA and MgsA are functionally redundant in rescuing stalled replication forks, and that the DNA repair and homologous recombination functions of RecA are separated from its function to maintain progression of replication fork. [source] DNA damage induction of recA in Mycobacterium tuberculosis independently of RecA and LexAMOLECULAR MICROBIOLOGY, Issue 3 2002Elaine O. Davis Summary The ubiquitous and highly conserved RecA protein is generally expressed from a single promoter, which is regulated by LexA in conjunction with RecA. We show here using transcriptional fusions to a reporter gene that the Mycobacterium tuberculosis recA gene is expressed from two promoters. Although one promoter is clearly regulated in the classical way, the other remains DNA damage inducible in the absence of RecA or when LexA binding is prevented. These observations demonstrate convincingly for the first time that there is a novel mechanism of DNA damage induction in M. tuberculosis that is independent of LexA and RecA. [source] Effects of recombinase A deficiency on biofilm formation by Streptococcus mutansMOLECULAR ORAL MICROBIOLOGY, Issue 2 2009S. Inagaki Background/aim:, Recombinase A (RecA) is essential for the transformation of both plasmid and chromosomal DNA in Streptococcus pneumoniae and is considered to be related to the SOS-response in Streptococcus mutans. Methods:, In the present study, a RecA-deficient mutant strain (RAD) was constructed by insertional inactivation of the recA gene encoding the RecA protein in strain MT8148 of S. mutans, after which the biological functions of acid tolerance and biofilm formation were investigated. Results:, RAD showed reduced acid tolerance and produced lower density biofilm compared with the wild-type strain. In addition, confocal microscopic observation indicated that the biofilm produced by RAD was composed of cells with significantly lower viability compared with that produced by strain MT8148. Conclusion:, These results suggest that RecA has a relationship with biofilm formation. [source] Sensitivity Enhancement in Two-Dimensional Solid-State NMR Spectroscopy by Transverse MixingCHEMPHYSCHEM, Issue 6 2004Robert Tycko Dr. Abstract The sensitivity of two-dimensional (2D) 13C,13C solid-state NMR spectroscopy under magic-angle spinning (MAS) is shown to be enhanced by the use of transverse polarization transfer in place of the conventional longitudinal polarization transfer. Experimental results are reported for 2D spectroscopy of a 20-residue, filament-forming peptide derived from the E. coli RecA protein, containing five uniformly 13C-labeled residues, performed at 14.1 T with high-speed MAS and with finite-pulse radio-frequency-driven recoupling of dipolar interactions in the mixing period. Significant sensitivity enhancements observed at short mixing periods result from a more rapid build-up of cross-peaks under transverse mixing than under longitudinal mixing and from the gain inherent in 2D measurements in which both orthogonal transverse polarization components in the t1 period contribute to each free-induction decay signal detected in the t2 period. [source] Titration of the Escherichia coli DnaA protein to excess datA sites causes destabilization of replication forks, delayed replication initiation and delayed cell divisionMOLECULAR MICROBIOLOGY, Issue 1 2003Morigen Summary In Escherichia coli, the level of the initiator protein DnaA is limiting for initiation of replication at oriC. A high-affinity binding site for DnaA, datA, plays an important role. Here, the effect of extra datA sites was studied. A moderate increase in datA dosage (, fourfold) delayed initiation of replication and cell division, but increased the rate of replication fork movement about twofold. At a further increase in the datA gene dosage, the SOS response was induced, and incomplete rounds of chromosome replication were detected. Overexpression of DnaA protein suppressed the SOS response and restored normal replication timing and rate of fork movement. In the presence of extra datA sites, cells showed a dependency on PriA and RecA proteins, indicating instability of the replication fork. The results suggest that wild-type replication fork progression normally includes controlled pausing, and that this is a prerequisite for normal replication fork function. [source] | ||||||||||