Referenced in: none

Automatically associated channels: Kir2.3

Title: gamma-Butyrolactone autoregulator-receptor system involved in lankacidin and lankamycin production and morphological differentiation in Streptomyces rochei.

Authors: Kenji Arakawa, Susumu Mochizuki, Kohei Yamada, Takenori Noma, Haruyasu Kinashi

Journal, date & volume: Microbiology (Reading, Engl.), 2007 Jun , 153, 1817-27

PubMed link: http://www.ncbi.nlm.nih.gov/pubmed/17526839

Abstract
An afsA homologue (srrX) and three gamma-butyrolactone receptor gene homologues (srrA, srrB and srrC) are coded on the giant linear plasmid pSLA2-L in Streptomyces rochei 7434AN4, a producer of two polyketide antibiotics, lankacidin and lankamycin. Construction of gene disruptants and their phenotypic study revealed that srrX and srrA make a gamma-butyrolactone receptor system in this strain. Addition of a gamma-butyrolactone fraction to an srrX-deficient mutant restored the production of lankacidin and lankamycin, indicating that the SrrX protein is not necessary for this event. In addition to a positive effect on antibiotic production, srrX showed a negative effect on morphological differentiation. The receptor gene srrA reversed both effects of srrX, while the second receptor gene homologue srrC had only a positive function in spore formation. Furthermore, disruption of the third homologue srrB greatly increased the production of lankacidin and lankamycin. Electron microscopic analysis showed that aerial mycelium formation stopped at a different stage in the srrA and srrC mutants. Overall, these results indicated that srrX, srrA, srrB and srrC constitute a complex regulatory system for antibiotic production and morphological differentiation in S. rochei.