M Labazi | PubMed Health

PubMed1999

A consensus sequence for the Rhodospirillaceae SOS operators.

The sequences controlling the expression of the Rhodobacter capsulatus recA and uvrA genes belonging to the SOS DNA repair system have been identified by PCR mutagenesis. Data obtained demonstrated that the GTTCN7GTAC and GAACN7GAAC motifs present upstream of the recA gene and the GTTCN7GTTC motif found upstream of the uvrA gene are required for their respective DNA damage-mediated induction. Alignment of recA promoters of R. capsulatus, Rhodobacter sphaeroides and Rhodopseudomonas viridis with the uvrA promoters of R. capsulatus and R. sphaeroides has identified the consensus sequence GTTCVYVYTWTGTTC as the SOS operator site of the Rhodospirillaceae family.

Adenosine Triphosphatases↗

PubMed1997

Functional analysis of the recA promoter of Rhodobacter capsulatus.

Expression of the Rhodobacter capsulatus recA gene is inducible by DNA damage. By using primer extension and serial deletion, we have identified the promoter of the R. capsulatus recA gene. Electrophoretic mobility-shift assays experiments have shown that a protein binds to a region of the R. capsulatus recA promoter containing the imperfect palindromic TTGTACTCATACCATGAGAACAA, which is centered on position-8 with respect to the transcriptional starting site. PCR mutagenesis of both halves of this palindrome indicates that the TTGT and ACAA motifs are necessary both for normal DNA-protein complex formation in vitro and for full DNA damage-mediated induction of recA. Nevertheless, the basal level of recA expression is not increased when both halves of the TTGTN15ACAA sequence are mutagenized. These data suggest that the R. capsulatus recA gene may be regulated by a positive transcription factor which binds to this palindrome.

Base Sequence↗