The binding and transport of DNA by competent Bacillus subtilis requires the assembly of a specialized apparatus. We present here the characterization of comE, an operon under competence control that is required for both DNA binding to the competent ceil surface, and for uptake. comE contains three open reading frames (0RF1‐3) read in the forward direction, preceded by a long untranslated leader sequence and an apparent EσA promoter. A minor promoter also is responsible for transcription of ORF2 and ‐3. A transcript containing a single ORF is produced in the reverse direction. The reverse ORF overlaps ORF1 and the untranslated comE leader. The comE transcript is present at a very low level during growth and at an elevated level in stationary‐phase cells. Converseiy, the reverse transcript is present during exponential growth and disappears during stationary phase. The reverse ORF resembles prokaryotic and eukaryotic pyrroiine‐5‐carboxylate reductases, while ORF2 is similar to several dCMP deaminases. 0RF1 and 0RF3 are predicted to be integral membrane proteins. The latter is specifically required for DNA uptake but not for binding.
|Original language||English (US)|
|Number of pages||13|
|State||Published - Oct 1993|
ASJC Scopus subject areas
- Molecular Biology