Premium
Polynucleotide phosphorylase is necessary for competence development in Bacillus subtilis
Author(s) -
Luttinger Amy,
Hahn Jeanette,
Dubnau David
Publication year - 1996
Publication title -
molecular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 247
eISSN - 1365-2958
pISSN - 0950-382X
DOI - 10.1046/j.1365-2958.1996.380907.x
Subject(s) - bacillus subtilis , biology , polynucleotide phosphorylase , competence (human resources) , computational biology , microbiology and biotechnology , biochemistry , genetics , enzyme , bacteria , purine nucleoside phosphorylase , purine , psychology , social psychology
comR ( pnpA ) is a newly identified gene in Bacillus subtilis that is necessary for the expression of late competence genes. Transformability of a comR ( pnpA ) mutant is 1–5% of that seen in comR + strains. Cloning and sequencing identified ComR as polynucleotide phosphorylase (PNPase). The PNPase amino acid sequence has 50% identity and 67% similarity with the Escherichia coli enzyme. Enzymatic assays show that this is the only PNPase activity in B. subtilis comR ( pnpA ) is necessary for comG–lacZ and comK–lacZ expression, but this requirement is bypassed by a mecA disruption. In B. subtilis , the loss of PNPase has little effect on expression from a fusion of the srfA promoter directly to lacZ, butis necessary for normal expression from certain srfA–lacZ fusions that include portions of the normal srfA transcript. When a srfA–lacZ translational fusion is tested in isogenic pnpA + and pnpA derivatives of E. coli , lower expression is seen in the pnpA mutant. Since expression from lacZ fusions to comA sinR , and mecA appeared similar in the B. subtilis pnpA and pnpA + strains, the loss of PNPase does not have a strong general effect on gene expression. These results suggest that PNPase may be necessary for modification of the srfA transcript in order to activate translation or stabilize the transcript, and that this may be necessary for competence development. This is the first evidence of post‐transcriptional effects on the development of competence in B. subtilis