RESUMEN
A new shuttle cosmid vector, pKC505, was constructed for the cloning of Streptomyces DNA. This vector, which can be conjugally transferred between different streptomycetes, was used to construct a genomic library from a spiramycin-producing S. ambofaciens strain. By transformation of the spiramycin-sensitive S. griseofuscus with the library, three phenotypically different spiramycin-resistance genes were isolated. S. ambofaciens DNA in these clones was colinear with the chromosome, and the cloned DNA was stable in E. coli, S. griseofuscus and S. fradiae. These cosmids could be isolated easily from S. griseofuscus, an improvement over the previous shuttle cosmid vector, pKC462a [Stanzak et al., Bio/Technology 4 (1986) 229-232], which was somewhat difficult to isolate from S. lividans.
Asunto(s)
Cósmidos , Leucomicinas/genética , Streptomyces/genética , Streptomycetaceae/genética , Mapeo Cromosómico , Clonación Molecular , Farmacorresistencia Microbiana , Escherichia coli/genética , Hibridación de Ácido Nucleico , PlásmidosRESUMEN
Insertion sequences (IS) are discrete segments of DNA that can transpose from one genomic site to another and promote genetic rearrangements. A question that is central to understanding the mechanism of transpositional recombination is whether genetic rearrangements are accompanied by duplication of the IS that promotes them. Analysis of adjacent deletions mediated by IS903 provides the strongest evidence to date than any IS-mediated transpositional recombination can occur by an efficient replicative mechanism.