Expression analysis of the ssgA gene product, associated with sporulation and cell division in Streptomyces griseus.
The ssgA gene of Streptomyces griseus B2682, when present in high copy number, results in both suppression of sporulation and fragmented growth of mycelia. Western analysis with polyclonal antibodies against the gene product (SsgA) revealed a close correlation between SsgA accumulation and the onset of sporulation in wild-type cells. The protein was only detected in the cytoplasm. Certain developmental mutants of S. griseus (afs, reIC and brgA) which are defective in aerial mycelium formation in solid culture and submerged spore formation in liquid culture failed to accumulate SsgA. The SsgA protein appeared shortly (1 h) after nutritional shift-down of strain B2682 cells. afs mutant cells sporulated and expressed SsgA only when A-factor was present both before and after nutritional shift-down. Introduction of the ssgA gene in a low-copy-number vector into strain B2682 resulted in fivefold overexpression of SsgA, and was accompanied by fragmented growth of mycelia and suppression of submerged spore formation (in liquid culture) and aerial mycelium formation (in solid culture). Streptomycin production was not inhibited. In a control experiment, a nonfunctional ssgA gene possessing a frameshift mutation near its N-terminus had no effect on either growth or sporulation. It is proposed that the ssgA gene product plays a role in promoting the developmental process of S. griseus.
Kawamoto
Shinichi
S
National Food Research Institute, 2-1-2 Kannondai, Tsukuba, Ibaraki 305, Japan.
Watanabe
Hajime
H
National Food Research Institute, 2-1-2 Kannondai, Tsukuba, Ibaraki 305, Japan.
Hesketh
Andrew
A
National Food Research Institute, 2-1-2 Kannondai, Tsukuba, Ibaraki 305, Japan.
Ensign
Jerald C
JC
Department of Bacteriology, 1550 Linden Drive, University of Wisconsin-Madison, Madison, WI 53706, USA.
Ochi
Kozo
K
National Food Research Institute, 2-1-2 Kannondai, Tsukuba, Ibaraki 305, Japan.
D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000235:genetics*; D001483:Base Sequence; D002451:Cell Compartmentation; D002455:Cell Division / Q000235:genetics*; D003470:Culture Media; D003593:Cytoplasm / Q000737:chemistry; D016368:Frameshift Mutation; D018628:Gene Dosage; D015964:Gene Expression Regulation, Bacterial; D005798:Genes, Bacterial; D008969:Molecular Sequence Data; D013171:Spores, Bacterial / Q000166:cytology / Q000502:physiology; D013305:Streptomyces griseus / Q000166:cytology / Q000502:physiology*
D001426:Bacterial Proteins; D003470:Culture Media