ANALYSIS OF THE BACILLUS-SUBTILIS S10 RIBOSOMAL-PROTEIN GENE-CLUSTER IDENTIFIES 2 PROMOTERS THAT MAY BE RESPONSIBLE FOR TRANSCRIPTION OF THE ENTIRE 15-KILOBASE S10-SPC-ALPHA CLUSTER

We have sequenced a previously uncharacterized region of the Bacillus subtilis S10 ribosomal protein gene cluster. The new segment includes genes for S10, L3, L4, L23, L2, S19, L22, S3, and part of L16. These B . subtilis genes map in the same order as the genes in the Escherichia coli S10 ribosomal protein operon. Two potential promoter sequences w ere identified, one similar to 200 bases and the other similar to 140 bases upstream of the S10 gene. The activities of the two promoters we re demonstrated by primer extension analysis, in vitro transcription e xperiments, and in vivo promoter fusion plasmid studies. In agreement with previous reports, our Northern analysis of exponentially growing cells failed to identify terminators or other active promoters within the S10-spc-alpha region. Our observations suggest that the two S10 pr omoters reported here are responsible for transcribing a 15-kb-long tr anscript for all of the genes in the B. subtilis S10, spc, and S10 clu sters.