中国生物工程杂志

[Objective: AtrA (AtrA-c) was characterized as a transcriptional activator for actII-ORF4 gene which encoding a pathway-specific transcriptional activator of the actinorhodin biosynthetic gene cluster in Streptomyces coelicolor A3(2). Two atrA homologues in Streptomyces griseus NBRC13350 and Streptomyces avermitilis MA-4680 were identified to be regulators for the production of streptomycin and avermectin B1a respectively. This study aimed to identify and clone a new atrA homologue in Streptomyces globisporus C-1027 that can produce a chromoprotein antitumor antibiotic lidamycin. [Methods] Heterologous expression of AtrA-c, Southern blotting, PCR, sequencing and bioinformatic analysis were used in this study. [Results] The heterologous expression of AtrA-c in S. globisporus C-1027 reduced the production of lidamycin production. Southern blotting analysis revealed that the S. globisporus C-1027 genome contains at least one copy of atrA-c homologue (atrA-gl). atrA-gl and flanking gene fragments were successfully amplified with the primers designed by the alignment of amino acid sequences of AtrA from distinct Streptomyces (GenBank/EMBL/DDBJ accession number GU723707). The alignments of amino acid sequences showed AtrA-gl shares highly conserved sequences with other homologous AtrA proteins, with a percentage of identity ranging from 65% to 87% and similarity ranging from 70% to 89%. The alignments of amino acid sequences of the flanking gene fragments suggested four atrA genes have identical arrangement in their genomic context. Phylogenetic analysis showed that S. globisporus AtrA-gl and S. griseus AtrA-g have a relatively more closer relationship. [Conclusion] atrA-gl is the first cloned transcriptional regulator located outside the gene cluster in S. globisporus C-1027 for lidamycin production. The data presented here set the stage for subsequent studies to elucidate the regulation of C-1027 biosynthesis, as well as for designing strategies for the construction of strains with enhanced C-1027 production.