title: [Plasmid pCQ4 and its phage phiCQ4 of endophytic Streptomyces sp. from Artemisia annua L].
abstract: OBJECTIVE
  Large plasmid pCQ4 was detected in Streptomyces sp. W75 from Artemisia annua L. We clonined, sequenced, analyzed and characterized pCQ4.
  
  
  METHODS
  Southern hybridization was used to determine restriction map of pCQ4. To clone the full-length of pCQ4, conjugation and recombinational cloning in a BAC vector were used.
  
  
  RESULTS
  The complete nucleotide sequence of pCQ4 consisted of 84833-bp, encoding 129 ORFs which 40 ORFs resembled these of bacterial phages. W75 culture could infect W75 cured of pCQ4 and formed plaques on plate. Phage particle (phiCQ4) was observed by transmission electron microscopy. LinearphiCQ4 DNA was detected on pulsed-field gel electrophoresis. Comparison to Streptomyces plasmid-phage pZL12, genes encoding major phage structural proteins resembled that of pCQ4.
  
  
  CONCLUSIONS
  Streptomyces plasmid pCQ4 could be transformed into lytic phagephiCQ4, and the phage segment on pCQ4 might be a mobile unit.
authors.affiliation: Key Laboratory of Synthetic Biology, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200032, China. qxcheng1981@msn.com
authors.forename: Qiuxiang
authors.initials: Q
authors.lastname: Cheng
authors.forename: Li
authors.initials: L
authors.lastname: Zhong
authors.forename: Zhongjun
authors.initials: Z
authors.lastname: Qin
mesh_terms: D031172:Artemisia annua / Q000382:microbiology*; D001435:Bacteriophages / Q000235:genetics*; D015139:Blotting, Southern; D022202:Chromosomes, Artificial, Bacterial / Q000235:genetics; D003001:Cloning, Molecular; D060026:Endophytes / Q000821:virology*; D004926:Escherichia coli / Q000235:genetics; D010957:Plasmids / Q000032:analysis / Q000235:genetics*; D017422:Sequence Analysis, DNA; D013302:Streptomyces / Q000821:virology*