Sequence of the 5S rRNA gene and organization of ribosomal RNA operons in Streptomyces rimosus

Abstract

One Streptomyces rimosus ribosomal RNA gene set (rrnF) was cloned into pBR322 as 8.8 kilobase-pairs BamHI fragment and sequence of the 3' end of the operon with 5S rRNA gene was determined. 5S rRNA gene is 120 bp long and highly homologous with two other known 5S rRNA from Streptomyces. Remarkable sequence homology with S. ambofaciens rrnD operon exists in the 3' noncoding regions, including first transcription termination signal. S. rimosus rrnF operon contains second putative terminator which is absent in S. ambofaciens rrnD operon. tRNA genes were not found at the 3' end of rrnF operon. The number of rRNA operons in S. rimosus was defined by Southern hybridization analysis. S. rimosus possess six rRNA operons and all rRNA operons contain identical PstI fragment of 4.5 kb. rRNA genes in operons are separated by short intergenic regions and organized in the order 16S-23S-5S. Efforts to connect tRNA genes with S. rimosus rRNA operons were unsuccessful.