The turkey transcription factor Pit-1/GHF-1 can activate the turkey prolactin and growth hormone gene promoters in Vitro but is not detectable in lactotrophs in vivo

Kristy L. Weatherly, Ramesh Ramachandran, Heather Strange, Kerry L. Waite, Brian Storrie, John A. Proudman, Eric A. Wong

Research output: Contribution to journalArticle

16 Scopus citations

Abstract

The transcription factor Pit-1/GHF-1 plays an important role in regulating the prolactin (Prl) and growth hormone (GH) genes in mammals. In this study, the role that Pit-1 plays in regulating the prolactin and growth hormone genes in avian species was examined by cotransfection assays and immunofluorescence staining of pituitary sections. In cotransfection assays, turkey Pit-1 activated the turkey Prl, turkey GH, and rat Prl promoters 3.8-, 3.7-, and 12.5-fold, respectively. This activation was comparable to rat Pit-1 activation of these same promoters. A point mutation in the turkey Pit-1 cDNA, which changed leu-219 to ser-219, resulted in a 2-, 2-, and 10-fold reduction in the activation of the turkey Prl, turkey GH, and rat Prl promoters, respectively. Unexpectedly, coexpression of tPit-1 (leu-219) and tPit-1(ser-219) activated turkey Prl and rat Prl promoters 9.4- and 35.9-fold, respectively, but had no effect on the turkey GH promoter. Dual-label immunofluorescence analysis of turkey pituitary sections revealed that Pit-1 was not detectable in prolactin-staining cells but was detectable in GH-staining cells. Taken together, these data indicate that in the domestic turkey, Pit-1 can activate the turkey Prl promoter in vitro, but does not appear to play a role in regulating Prl gene expression in vivo. Pit-1, however, still likely plays a role in regulating GH gene expression.

Original languageEnglish (US)
Pages (from-to)244-253
Number of pages10
JournalGeneral and Comparative Endocrinology
Volume123
Issue number3
DOIs
StatePublished - Jan 1 2001

All Science Journal Classification (ASJC) codes

  • Animal Science and Zoology
  • Endocrinology

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