Difference between revisions of "Part:BBa K1668002"

Revision as of 09:43, 11 September 2015

frr (from Streptomyces avermitilis, increasing avermectin production)

frr gene encodes the ribosome recycling factor (RRF), which is involved in the release of ribosomes from the translational post-termination complex for a new round of initiation. Avermectin yield was increased significantly by 3- to 3.7-fold in transformants 31267(pFRR-1139) and 31267(pFRRerm-1139), compared with that in the wild-type strains and both of the transformants contained multiple frr copies,. The avermectin productivity of each culture was quantitatively measured by HPLC analysis.

Research indicated that frr overexpression promoted cell growth as well as the expression of ave genes (including pathway-specific positive regulatory gene aveR for avermectin biosynthesis and ave structural genes), leading in turn to avermectin overproduction. Different from S-adenosylmethionine synthetase gene (metK), frr gene revealed a ‘‘copy number effect’’. That is to say, multiple copies of frr had a greater promoting effect on avermectin production than a single copy does. However, the detailed mechanism of frr enhancing antibiotic production remains to be clarified.

Compared with the wild-type strain, the effect of frr on avermectin production in engineered strains 76-02-e and GB-165 was less obvious, probably because most of the negative stimulatory factors are downregulated and most of the positive factors are upregulated, resulting in relatively limited potential for further improvement of avermectin yield.

【reference】 Li, L., et al. (2010). "Overexpression of ribosome recycling factor causes increased production of avermectin in Streptomyces avermitilis strains." J Ind Microbiol Biotechnol 37(7): 673-679.

Sequence and Features