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Abstract
The Streptomyces coelicolor genome harbors six copies of divergent large subunit (LSU) rRNA genes that constitute five kinds of LSU rRNA species in a cell. We report here that each heterogeneous LSU rRNA species is differentially expressed during morphological development. However, differential expression of rRNA species was not affected by depletion of a specific nutrient such as carbon, nitrogen, or phosphate from the culture medium. Analysis of the upstream region of the rRNA operons revealed that each operon contains a different composition of conserved rRNA gene promoters, indicating that each operon is independently regulated at the transcriptional level. These findings imply the existence of a regulatory mechanism that controls the independent expression of each LSU rRNA and a possible role of different species of LSU rRNA in posttranscriptional regulation of gene expression during the life cycle of this developmentally complex microorganism. [PUBLICATION ABSTRACT]