Streptomyces coelicolor

Streptomyces coelicolor is a soil-dwelling Gram-positive bacterium that belongs to the genus Streptomyces. The genome of one strain of S. coelicolor was sequenced in 2002. It contains 8,667,507 bp, encoding 7,825 predicted genes, including over 20 gene clusters for the synthesis of known or predicted natural products. Bacterial small RNAs are involved in post-transcriptional regulation. Using deep sequencing S. coelicolor transcriptome was analysed at the end of exponential growth. 63 small RNAs were identified. Expression of 11 of them was confirmed by Northern blot. The sRNAs were shown to be only present in Streptomyces species. sRNA scr4677 (Streptomyces coelicolor sRNA 4677) is located in the intergenic region between anti-sigma factor SCO4677 gene and a putative regulatory protein gene SCO4676. scr4677 expression requires the SCO4677 activity and scr4677 sRNA itself seem to affect the levels of the SCO4676-associated transcripts. Targets of two of S. coelicolor noncoding RNAs have been identified. Noncoding RNA of Glutamine Synthetase I was shown to modulate antibiotic production. The small RNA scr5239 (Streptomyces coelicolor sRNA upstream of SCO5239) has two targets. It inhibits agarase DagA expression by direct base pairing to the dagA coding region, and it represses translation of methionine synthase metE (SCO0985) at the 5' end of its open reading frame. Strains of S. coelicolor produce various antibiotics, including actinorhodin, methylenomycin, undecylprodigiosin, and perimycin. Certain strains of S. coelicolor can be used for heterologous protein expression.