Identification and Characterization of Potential Target Genes Critical for Doxorubicin Overproduction Using Streptomyces DNA Microarray Systems

초록

Doxorubicin is a highly-valuable anthracycline-family polyketide drug with a very potent anticancer activity, typically produced by a Gram-positive soil bacterium called Streptomyces peucetius. Thanks to the recent development of Streptomyces genomics-based technologies, the random mutagenesis approach for Streptomyces strain improvement has been switched toward the genomics-based technologies including the application of DNA microarray systems. In order to identify and characterize the genomics-driven potential target genes critical for doxorubincin overproduction, three different types of doxorubicin overproducing strains, a dnrI (doxorubicin-specific positive regulatory gene)-overexpressor, a doxA (gene involved in the conversion from daunorubicin to doxorubicin)-overexpressor, and a recursively-mutated industrial strain, were generated and examined their genomic transcription profiles using Streptomyces DNA microarray systems. Both the growth-phase-dependent RNA samples isolated from the wild-type and the overproducer were labeled using Cy3- and Cy5-fluorescence dyes, respectively, followed by the competitive hybridization with the doxorubicin-biosynthetic DNA chip as well as S. coelicolor whole genome chip. The DNA microarray results revealed several potential target genes in S. peucetius genome, whose expressions were significantly either up- or down-regulated comparing with the wild-type strain and were verified the effect of each gene on doxorubicin productivity in S. peucetius. A systematic understanding of doxorubicin overproduction at the genomic level presented in this research should lead us a rational design of molecular genetic strain improvement strategy.