Expression of the Bacillus subtilis acsA gene: position and sequence context affect cre-mediated carbon catabolite repression - PubMed (original) (raw)

Expression of the Bacillus subtilis acsA gene: position and sequence context affect cre-mediated carbon catabolite repression

J M Zalieckas et al. J Bacteriol. 1998 Dec.

Abstract

In Bacillus subtilis, carbon catabolite repression (CCR) of many genes is mediated at cis-acting carbon repression elements (cre) by the catabolite repressor protein CcpA. Mutations in transcription-repair coupling factor (mfd) partially relieve CCR at cre sites located downstream of transcriptional start sites by abolishing the Mfd-mediated displacement of RNA polymerase stalled at cre sites which act as transcriptional roadblocks. Although the acsA cre is centered 44.5 bp downstream of the acsA transcriptional start site, CCR of acsA expression is not affected by an mfd mutation. When the acsA cre is centered 161.5 bp downstream of the transcriptional start site for the unregulated tms promoter, CCR is partially relieved by the mfd mutation. Since CCR mediated at an acsA cre centered 44.5 bp downstream of the tms start site is not affected by the mfd mutation, the inability of Mfd to modulate CCR of acsA expression most likely results from the location of the acsA cre. Higher levels of CCR were found to occur at cre sites flanked by A+T-rich sequences than at cre sites bordered by G and C nucleotides. This suggests that nucleotides adjacent to the proposed 14-bp cre consensus sequence participate in the formation of the CcpA catabolite repression complex at cre sites. Examination of CCR of acsA expression revealed that this regulation required the Crh and seryl-phosphorylated form of the HPr proteins but not glucose kinase.

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Figures

FIG. 1

FIG. 1

cre DNA sequences. The HUT924 sequence corresponds to the hut cre and flanking DNA present in the HUT924 lacZ fusion (P_tms_ -hut cre-lacZ). The ACS7 sequence corresponds to the acsA cre with its flanking DNA present in ACS7 (acsA-lacZ) and is shown in reverse text. HUT940, HUT942, and HUT948 were derived from HUT924; the nucleotides shown in reverse text denote the positions within the hut cre that were changed to match the sequence of the acsA cre (ACS7). The TMS922 sequence corresponds to DNA located 44.5 bp downstream of the tms promoter (30). TMS951 and TMS952 were derived from TMS922; the nucleotides shown in reverse text denote nucleotides downstream of the tms promoter that were changed to match the sequence of the acsA cre.

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References

    1. Atkinson M R, Wray L V, Jr, Fisher S H. Regulation of histidine and proline degradation enzymes by amino acid availability in Bacillus subtilis. J Bacteriol. 1990;172:4758–4765. - PMC - PubMed
    1. Biaudet V, Samson F, Anagnostopoulos C, Ehrlich S D, Bessières P. Computerized genetic map of Bacillus subtilis. Microbiology. 1996;142:2669–2729. - PubMed
    1. Bryan E M, Beall B W, Moran C P., Jr A ςE-dependent operon subject to catabolite repression during sporulation in Bacillus subtilis. J Bacteriol. 1996;178:4778–4786. - PMC - PubMed
    1. Chambers S P, Prior S E, Barstow D A, Minton N P. The pMTL nic− cloning vectors. I. Improved pUC polylinker regions to facilitate the use of sonicated DNA for nucleotide sequencing. Gene. 1988;68:139–149. - PubMed
    1. Chauvaux S, Paulsen I T, Saier M H., Jr CcpB, a novel transcription factor implicated in catabolite repression in Bacillus subtilis. J Bacteriol. 1998;180:491–497. - PMC - PubMed

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