Identification of Novel Developmental Genes in Streptomyces coelicolor Using Random Mutagenesis

Streptomyces species are gram positive filamentous soil bacteria found worldwide. They are known for their ability to synthesize over two‐thirds of the antibiotics in use today. The Streptomyces genome is the largest bacterial genome to be sequenced thus far and contains the largest known amount of genes within a single bacterium. Many of these genes are involved in the complex program of development that is characteristic of this bacterial genus. The purpose of this study was to identify new genes involved in the development of Streptomyces coelicolor through random transposon mutagenesis of the wild‐type strain followed by visual screens. Candidates exhibiting potential developmental defects were then analyzed using phase‐contrast microscopy. To identify the site of transposon insertion, chromosomal DNA was isolated, subjected to restriction enzyme digestion and subsequent ligation followed by inverse polymerase chain reaction (PCR) and sequencing. Both known developmental genes and novel genes were identified through this process. Known developmental genes were identified such as whiH, indicating that the visual screens are working. Among the four novel genes identified were genes that encode a possible ATP/GTP binding protein, a putative monooxygenase, a putative membrane protein of unknown function, and a probable polyketide synthase. The mutants have already been partially characterized using microscopy and deletion mutations are currently being constructed to verify that the transposon insertions are causing the developmental phenotypes. Many additional developmental genes are believed to exist in this pharmacologically important bacterial genus, and this research provides multiple genes of interest for further study.