title: [Time course of let-7a expression in the cell cycle of human cervical carcinoma HeLa cells].
abstract: OBJECTIVE
  To investigate the time course of let-7a microRNA expression in the cell cycle of HeLa cells.
  
  
  METHODS
  HeLa cells were synchronized in G(1), S and G(2)/M phases using double-thymidine block, and the cell cycle phases were defined by flow cytometry. Real-time quantitative RT-PCR was used to examine the expression of let-7a in HeLa cells in different cell cycle phases.
  
  
  RESULTS
  The synchronization rates of G(1), S and G(2)/M phases were 84.81%, 83.65% and 77.69%, respectively. Let-7a was constitutively expressed throughout the cell cycle in HeLa cells, but the expression levels in G(1) and S phases were lower than those in G(2)/M phase.
  
  
  CONCLUSIONS
  Cell cycle can significantly influence the expression level of let-7a, which may provide new clues to the understanding of the cell cycle control mechanisms.
authors.affiliation: Institute of Genetic Engineering, Southern Medical University, Guangzhou, China. zhoujueyu@126.com
authors.forename: Jue-Yu
authors.initials: JY
authors.lastname: Zhou
authors.forename: Wen-Li
authors.initials: WL
authors.lastname: Ma
authors.forename: Hai-Lang
authors.initials: HL
authors.lastname: Yu
authors.forename: Wei-Wei
authors.initials: WW
authors.lastname: Xiao
authors.forename: Wen-Ling
authors.initials: WL
authors.lastname: Zheng
mesh_terms: D002453:Cell Cycle / Q000235:genetics*; D015972:Gene Expression Regulation, Neoplastic / Q000502:physiology*; D006367:HeLa Cells; D006801:Humans; D035683:MicroRNAs / Q000235:genetics / Q000378:metabolism*
chemical_list: D035683:MicroRNAs; C487931:mirnlet7 microRNA, human