title: [Expression of origin recognition complex 1 gene in DNA replication of vascularsmooth muscle cells].
abstract: OBJECTIVE
  To explore the expression of origin recognition complex 1 (ORC1) during the DNA replication of vascular muscle cells (VSMC).
  
  
  METHODS
  VSMC of thoracic aorta in rats were obtained by the adherence method of tissue culture. The cell synchrony was obtained by the method of double-thymidine block, colchicine treatment and serum starvation. The expression of ORC1 mRNA at different cell cycles of VSMC was determined by RT-PCR and the protein expression of ORC1 was analyzed by Western blot.
  
  
  RESULTS
  Cultured VSMC were identified by light microscope and immunocytochemistry. Significant expression of ORC1 mRNA and protein in a quiescent stage of VSMC were not observed. Upon synchronization, the expression of ORC1 mRNA was significantly higher at G(1)/S phase of VSMC than that at S and G(2)/M phases. The expression of ORC1 protein followed same changes as the ORC1 mRNA expression at different stages of cell cycles.
  
  
  CONCLUSIONS
  ORC1 may be an important regulatory factor at the initiation of proliferative process of VSMC.
authors.affiliation: Department of Cardiology, South-west Hospital, Third Military Medical University, Chongqing 400038, China.
authors.forename: Ming-Hong
authors.initials: MH
authors.lastname: Jiang
authors.forename: Mao-Qin
authors.initials: MQ
authors.lastname: Shu
authors.forename: Yue-Long
authors.initials: YL
authors.lastname: Qin
authors.forename: Qian
authors.initials: Q
authors.lastname: Wang
mesh_terms: D000818:Animals; D001013:Aorta, Thoracic / Q000166:cytology; D015153:Blotting, Western; D002453:Cell Cycle; D049109:Cell Proliferation; D002478:Cells, Cultured; D004247:DNA / Q000235:genetics*; D004261:DNA Replication; D015972:Gene Expression Regulation, Neoplastic; D008297:Male; D009131:Muscle, Smooth, Vascular / Q000166:cytology; D032389:Myocytes, Smooth Muscle / Q000378:metabolism*; D051738:Origin Recognition Complex / Q000096:biosynthesis* / Q000235:genetics / Q000502:physiology; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D020133:Reverse Transcriptase Polymerase Chain Reaction
chemical_list: C497223:ORC1 protein, human; D051738:Origin Recognition Complex; D012333:RNA, Messenger; D004247:DNA