NsdB, A Gene Negatively Affecting Antibiotics Production In Streptomyces

Gene nsdA was found to be negatively affecting the differentiation of Streptomyces coelicolor A3(2). The S. coelicolor DNA sequence had been finished and according to it we found gene SCO7252 and SCO1593's sequence were identity to it, and all of the three genes' protents have a TPR-like domain. This study tried to find out the function of the gene SCO7252 and SCO1593.Firstly, this study constructed the gene disruption vectors of SCO7252 and SCO1593, transformed them into the S. coelicolor A3(2) M145 by conjugation, and we obtained three gene disrupted strains for each successfully. On MS agar, only SCO7252 null mutants produced more actinorhodin and CDA than wild type strain, but did not alter the morphological differentiation. SCO1593 gene disruption did not alter the phenotype.We named SCO7252 nsdB following nsdA. The expression of nsdB was initiated at about 30 h, which was similar to nsdA. Inorder to know the relationship between nsdA and nsdB, this study constructed the single-copy-number and high-copy-number plasmids carring nsdA can be introduced into ZL2. In the same way, we constructed the single-copy-number and high-copy-number plasmids carring nsdB can be introduced into LW9. On MS agar, we found after being introduced additional high-copy-number nsdB, LW9 restored to wild type strain.