DELETION ANALYSIS OF THE AVERMECTIN BIOSYNTHETIC GENES OF STREPTOMYCES-AVERMITILIS BY GENE-CLUSTER DISPLACEMENT

Citation
T. Macneil et al., DELETION ANALYSIS OF THE AVERMECTIN BIOSYNTHETIC GENES OF STREPTOMYCES-AVERMITILIS BY GENE-CLUSTER DISPLACEMENT, Journal of bacteriology, 175(9), 1993, pp. 2552-2563
Citations number
48
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Microbiology
Journal title
ISSN journal
0021-9193
Volume
175
Issue
9
Year of publication
1993
Pages
2552 - 2563
Database
ISI
SICI code
0021-9193(1993)175:9<2552:DAOTAB>2.0.ZU;2-8
Abstract
Streptomyces avermitilis produces a group of glycosylated, methylated macrocyclic lactones, the avermectins, which have potent anthelmintic activity. A homologous recombination,strategy termed gene cluster disp lacement was used to construct Neo(r) deletion strains with defined en dpoints and to clone the corresponding complementary DNA encoding func tions for avermectin biosynthesis (avr). Thirty-five unique deletions of 0.5 to >100 kb over a continuous 150-kb region were introduced into S. avermitilis. Analysis of the avermectin phenotypes of tbe deletion -containing strains defined the extent and ends of the 95-kb avr gene cluster, identified a regulatory region, and mapped several avr functi ons. A 60-kb region in the central portion determines the synthesis of the macrolide ring. A 13-kb region at one end of the cluster is respo nsible for synthesis and attachment of oleandrose disaccharide. A 10-k b region at the other end has functions for positive regulation and C- 5 O methylation. Physical analysis of the deletions and of in vivo-clo ned fragments refined a 130-kb physical map of the avr gene cluster re gion.