title: Osteotesticular protein tyrosine phosphatase expression in rodent testis.
abstract: OBJECTIVE
  In the last decade the novel receptor-like protein tyrosine phosphatase was identified and termed osteotesticular tyrosine phosphatase (OST-PTP) due to its restricted expression in bone and testis. OST-PTP expression is regulated during osteoblast differentiation and it shows stage specific expression in the testis. Confined OST-PTP expression in the basal compartment of the seminiferous tubules suggests that this protein may be a good candidate for a rodent germ stem cell marker. To test this hypothesis we determined the exact pattern of OST-PTP expression in the rodent testis.
  
  
  METHODS
  Adult mouse and rat paraffinized testis sections were subjected to in situ hybridization using riboprobes against the receptor and catalytic domains of the protein OST-PTP.
  
  
  RESULTS
  OST-PTP testicular expression in rodents is not confined to the spermatogonia, as previously suggested, but is also present in Sertoli cells in a stage independent pattern. This finding excludes the hypothesis that OST-PTP is a germ stem cell identification marker in rodents. In addition, we report the identification of a testicular OST-PTP isoform lacking part of a catalytic domain that is widely expressed during spermatogenesis in all cell types.
  
  
  CONCLUSIONS
  This finding implies tight control over OST-PTP expression in the testis, which in turn suggests an important role for OST-PTP and its isoform in male germ cell differentiation.
authors.affiliation: Department of Molecular and Cellular Biology, Center for Gene Therapy and Scott Department of Urology, Baylor College of Medicine, Houston, Texas, USA.
authors.forename: Maria Rosa
authors.initials: MR
authors.lastname: Maduro
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Davis
authors.forename: Alan
authors.initials: A
authors.lastname: Davis
authors.forename: Dolores J
authors.initials: DJ
authors.lastname: Lamb
mesh_terms: D000818:Animals; D001842:Bone and Bones / Q000033:anatomy & histology / Q000201:enzymology; D005786:Gene Expression Regulation / Q000502:physiology; D008297:Male; D051379:Mice; D017027:Protein Tyrosine Phosphatases / Q000235:genetics / Q000378:metabolism*; D051381:Rats; D012708:Sertoli Cells / Q000000981:diagnostic imaging / Q000201:enzymology; D013091:Spermatogenesis / Q000235:genetics / Q000502:physiology*; D013093:Spermatogonia / Q000000981:diagnostic imaging / Q000201:enzymology; D013737:Testis / Q000033:anatomy & histology / Q000201:enzymology*; D014463:Ultrasonography
chemical_list: D017027:Protein Tyrosine Phosphatases