title: Two internal origins of replication in Streptomyces linear plasmid pFRL1.
abstract: Previous reports showed that Streptomyces linear plasmids usually contain one internal replication locus. Here, we identified two new replication loci on pFRL1, one (rep1A-ncs1) next to a telomere and another (rep2A-ncs2) approximately 10 kb from it. The rep1A-ncs1 locus was able to direct replication independently in both linear and circular modes, whereas rep2A-ncs2 required an additional locus, rlrA-rorA, in order to direct propagation in linear mode. Rep1A protein bound to ncs1 in vitro. By quantitative reverse transcription-PCR and Northern hybridization, we showed that transcription of rep1A and rep2A varied during development and that each dominated at different time points. pFRL1-derived linear plasmids were inherited through spores more stably than circular plasmids and were more stable with pSLA2 telomeres than with pFRL1 telomeres in Streptomyces lividans.
authors.affiliation: Key Laboratory of Synthetic Biology, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, 300 Fenglin Road, Shanghai 200032, China.
authors.forename: Ran
authors.initials: R
authors.lastname: Zhang
authors.forename: Shiyuan
authors.initials: S
authors.lastname: Peng
authors.forename: Zhongjun
authors.initials: Z
authors.lastname: Qin
mesh_terms: D004261:DNA Replication; D004269:DNA, Bacterial / Q000235:genetics* / Q000378:metabolism*; D004270:DNA, Circular / Q000235:genetics / Q000378:metabolism; D010957:Plasmids; D018741:Replication Origin; D048170:Streptomyces lividans / Q000235:genetics*
chemical_list: D004269:DNA, Bacterial; D004270:DNA, Circular