The genetic region (sitISR) located in a putative integrating element of Streptomyces albus ATCC 21838 was able to enhance biosyntheses of actinorhodin and undecylprodigiosin when introduced into Streptomyes lividans TK-24. The heterologous expression in S. lividans TK-24 indicated that sitS and sitR activated the antibiotic productions and sitI repressed the productions. The sitI-expression also repressed morphological development on regeneration agar. Promoter activity assay showed that the sitS-transcription was repressed by SitR. When sitI and sitR were co-expressed, the SitR-mediated activation of antibiotic production was repressed but derepressed after the growth ceased, resulting in growth-dissociated overproduction of undecylprodigiosin.