title: Characterization of a Streptomyces-lividans-type site-specific DNA modification system in the avermectin-producer Streptomyces avermitilis permits investigation of two novel giant linear plasmids, pSA1 and pSA2.
abstract: The degradation of Streptomyces avermitilis DNA samples analysed by conventional pulsed-field gel electrophoresis was shown to be due to Tris-dependent, double-strand cleavage. Using alternative electrophoretic conditions, separation of intact DNA molecules was achieved, permitting the identification of two novel giant linear plasmids: the 100 kb pSA1 and 250 kb pSA2. Use of pSA2 DNA as a probe showed that pSA1 does not cross-hybridize, indicating that the plasmids are not closely related. The site-specificity of the DNA modifications, which render the DNA susceptible to Tris-dependent cleavage, was found to be essentially identical to that of similar modifications found in the DNA of S. lividans.
authors.affiliation: Molecular Biology Research Group, School of Biological Sciences, University College of Swansea, Singleton Park, UK.
authors.forename: M
authors.initials: M
authors.lastname: Evans
authors.forename: F S
authors.initials: FS
authors.lastname: Kaczmarek
authors.forename: K
authors.initials: K
authors.lastname: Stutzman-Engwall
authors.forename: P
authors.initials: P
authors.lastname: Dyson
mesh_terms: D001426:Bacterial Proteins / Q000378:metabolism*; D015280:DNA Restriction-Modification Enzymes / Q000378:metabolism*; D004269:DNA, Bacterial / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D016521:Electrophoresis, Gel, Pulsed-Field / Q000379:methods*; D007559:Ivermectin / Q000031:analogs & derivatives* / Q000378:metabolism; D009693:Nucleic Acid Hybridization; D010957:Plasmids / Q000235:genetics*; D013045:Species Specificity; D013302:Streptomyces / Q000235:genetics*
chemical_list: D001426:Bacterial Proteins; D015280:DNA Restriction-Modification Enzymes; D004269:DNA, Bacterial; D007559:Ivermectin; C019264:avermectin