Structural and Functional Analysis of Pleiotropic Gene involved in Morphological and Metabolic Differentiation in Streptomyces

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This report describes the peculiarity of a strain BalA1 derived from Thiostrepton-producing streptomyces azureus PK100C and the structure and function of its kpnI-genomic fragment of 2.5kb cloned in a vector pMCP5.The 2.5kb DNA-inserting plasmid was named as pSAB931. The pSAB931-harboring BalA1 showed the following specific characters on the crossfeeding solid culture : It was impossble to form the aerial mycelia and spores by itself, but parent PK100C and its wild-type strain PKO, another Thiostrepton-producing S.laurentii and some other streptomycetes stimulated the formation of those of BalA1 ; it inhibited the growth of strains PK100C and PKO, S.laurentii and some other streptomycetes ; it induced the production of a red color antibiotic (Undecylprodigiosin) of S.coelicolor at early stage of growth.The 2.5kb fragment of pSAB931 was used to probe Southern blots in order to detect the presence of the homologus sequence in diverse bacterial genome. Blotting analysis allowed us to detect the hybridized signals on all twenty streptomyces species tested (strains PK100C and PKO, S.laurentii, S.coelicolor etc). This result shows that this sequence presents in the genome of many Streptomyces species and it is an important gene.The DNA fragment was sequenced. It contained 2498bp. The frame analysis revealed two open reding frames, ORF843 and ORF489. They had 843bp and 489bp, respectively. The amino acid sequences of their deduced products were compared with those registered in the databases. The putative ORF843 product was shown a high similarity with phosphoserine phophatase (psp product) of Mycobacterium leprae. It was also shown that the putative ORF489 product was similar to a seputm placement determinants (minD product) of Bacillus subtilis.These results suggest that two ORFs are the pleiotropic genes involved in the morphological and metabolic differentiation.