title: c-kit expression profile and regulatory factors during spermatogonial stem cell differentiation.
abstract: BACKGROUND
  It has been proven that c-kit is crucial for proliferation, migration, survival and maturation of spermatogenic cells. A periodic expression of c-kit is observed from primordial germ cells (PGCs) to spermatogenetic stem cells (SSCs), However, the expression profile of c-kit during the entire spermatogenesis process is still unclear. This study aims to reveal and compare c-kit expression profiles in the SSCs before and after the anticipated differentiation, as well as to examine its relationship with retinoic acid (RA) stimulation.
  
  
  RESULTS
  We have found that there are more than 4 transcripts of c-kit expressed in the cell lines and in the testes. The transcripts can be divided into short and long categories. The long transcripts include the full-length canonical c-kit transcript and the 3' end short transcript. Short transcripts include the 3.4 kb short transcript and several truncated transcripts (1.9-3.2 kb). In addition, the 3.4 kb transcript (starting from intron 9 and covering exons 10 ~ 21) is discovered to be specifically expressed in the spermatogonia. The extracellular domain of Kit is obtained in the spermatogonia stage, but the intracellular domain (50 kDa) is constantly expressed in both SSCs and spermatogonia. The c-kit expression profiles in the testis and the spermatogonial stem cell lines vary after RA stimulation. The wave-like changes of the quantitative expression pattern of c-kit (increase initially and decrease afterwards) during the induction process are similar to that of the in vivo male germ cell development process.
  
  
  CONCLUSIONS
  There are dynamic transcription and translation changes of c-kit before and after SSCs' anticipated differentiation and most importantly, RA is a significant upstream regulatory factor for c-kit expression.
authors.forename: Lei
authors.initials: L
authors.lastname: Zhang
authors.forename: Jiangjing
authors.initials: J
authors.lastname: Tang
authors.forename: Christopher J
authors.initials: CJ
authors.lastname: Haines
authors.forename: Huai
authors.initials: H
authors.lastname: Feng
authors.forename: Liangxue
authors.initials: L
authors.lastname: Lai
authors.affiliation: Shanghai first maternity and infant health hospital, Tongji University, Shanghai, China. xiaomingteng@hotmail.com.
authors.forename: Xiaoming
authors.initials: X
authors.lastname: Teng
authors.forename: Yibing
authors.initials: Y
authors.lastname: Han
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D002454:Cell Differentiation; D002460:Cell Line; D002478:Cells, Cultured; D005786:Gene Expression Regulation; D006801:Humans; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D019009:Proto-Oncogene Proteins c-kit / Q000235:genetics* / Q000378:metabolism*; D013093:Spermatogonia / Q000166:cytology* / Q000378:metabolism*; D013234:Stem Cells / Q000187:drug effects / Q000378:metabolism*; D013737:Testis / Q000378:metabolism; D059467:Transcriptome / Q000187:drug effects; D014212:Tretinoin / Q000378:metabolism / Q000494:pharmacology*
chemical_list: D014212:Tretinoin; D019009:Proto-Oncogene Proteins c-kit