Table 1.

Strains and plasmids used in this study

Strain or plasmidDescriptionSource or reference
Strains
S. ambofaciens ATCC 23877Wild-type strain 31
S. ambofaciens OS81Non-spiramycin-producing mutant of ATCC 23877 29
S. ambofaciensOS41.99Hmr; derivative of ATCC 23877, withgimA inactivated by gene replacementThis study
S. ambofaciens OS41.99NPHmr; derivative of OS81, with gimA inactivated by gene replacement
S. lividans OS456Hmr; derivative of TK21 (18), with lrm andmgt inactivated by gene replacement; highly sensitive to macrolides 30
M. luteusDSM1790Indicator strain, highly sensitive to macrolides
M. luteus Cgr Mutant strains ofM. luteus DSM1790, resistant to CGThis study
E. coli DH5αStrain used for DNA cloningClontech
E. coli S17.1Donor strain used for E. coli/Streptomycesconjugation 40
Plasmids
 pHP45 Ωhyg Apr Hmr; source of the Ωhyg cassette 10
 pWED1Apr; cosmid vector derived from pWE15 (44) by deletion of the 4.1-kbHpaI-HpaI fragment, removing the mammalian expression moduleThis study
 pIJ4070Apr; pIJ2925 (19) containing the ermE-up promoter mutant ermEp* (6) 5
 pIJ903Apr Nor; low-copy-numberStreptomyces/E. coli vector 22
 pOJ260Gnr; replicative vector in E. coli, nonreplicative in Streptomyces; used for conjugation experiments 7
 pOS41.78Apr; cosmid from the S. ambofaciens ATCC 23877 gene library in pWED1 hybridizing withsrmA This study
 pOS41.80Apr; derived from pOS41.78; 3.6-kb BamHI fragment hybridizing with the end of srmA cloned into pUC19 (Fig. 1)This study
 pOS41.85Apr; derived from pOS41.80;SgrAI-BamHI fragment cloned into pIJ4070BamHI (Fig. 1)This study
 pOS41.90Apr Nor; derived from pOS41.85; fragment containing ermEp* and gimAcloned into pIJ903 (Fig. 1)This study
 pOS41.105Apr Nor; derived from pOS41.90; in-frame deletion in gimA from NruI toSmaI (Fig. 1)This study
 pOS41.98Apr Hmr; derived from pOS41.80; NcoI-BamHI fragment with the internalSplI-SplI fragment replaced by Ωhyg(Fig. 1)This study
 pOS41.99GnrHmr; insert from pOS41.98 cloned into pOJ260 (Fig.1)This study