The bldA-encoded tRNA is poorly expressed in the bldi mutant of Streptomyces coelicolor A3(2)

Department of Biological Sciences, University of Alberta, Edmonton, Alberta, Canada T6G 2E9 Author for correspondence: Brenda K. Leskiw. Tel: +1 403 492 1868. Fax: + 1 403 492 9234. e-mail: brenda_leskiw@biology.ualberta.ca ABSTRACT The bldA gene, encoding a leucyl tRNA recognizing the UUA codon, is expressed at significantly lower levels in the bldii mutant, Streptomyces coelicolor J703, than in the parent S. coelicolor A3(2). Expression of a TTA-containing reporter gene was reduced in the bldi mutant, as was the mature, 87 nucleotide, form of the bldA -encoded tRNA. This reduced level of the tRNA was also seen when the bldA gene was introduced on a high-copy-number plasmid into the bldi mutant, suggesting that maximal bldA expression may require a bldii -dependent promoter. Keywords: Streptomyes coelicolor, bldA, bldl, antibiotic production, morphological differentiation