title: Identification of mammalian Pit-1w, possibly involved in spermatogenesis in mice.
abstract: Pit-1 is a pituitary-specific transcription factor responsible for pituitary development and hormone expression in mammals. Alternative splicing of Pit-1 gene transcripts has been shown to give rise to several variants with discrete transactivation properties; however, those arising from alternative promoters such as avian Pit-1 w have not yet been identified in mammals. Here, comparative genomics analysis followed by reverse transcription-polymerase chain reaction (RT-PCR) and rapid amplification of 5' cDNA ends (5'RACE) were used in identifying Pit-1 w mRNA in the mouse pituitary. The mouse Pit-1 w mRNA is generated by using an alternative promoter located in the first intron, as with chicken Pit-1 w, and is expressed in a wide variety of tissues besides the pituitary. In the testis, Pit-1 w is expressed as the predominant variant and a protein of 33 kDa. During the first wave of spermatogenesis, expression of Pit-1 w mRNA at substantial levels was observed from 3 weeks, but not at 1 or 2 weeks after birth. A combination of immunohistochemistry and in situ hybridization detected Pit-1 mRNA and Pit-1 immunoreactivity in the spermatogonia, spermatocytes, and spermatids in the testis of adult mice. Because secondary spermatocytes and haploid spermatids increase in number between 18 and 20 days after birth in mice, it is possible that mouse Pit-1 w plays a role in spermatogenesis. This is the first report demonstrating the expression of Pit-1 variants arising from alternative promoters in mammals.
authors: Graduate School of Natural Science and Technology, Okayama University, 3-1-1 Kitaku Tsushimanaka, Okayama 700-8530, Japan.
authors: Shusuke
authors: S
authors: Taniuchi
authors: Kazuki
authors: K
authors: Maeda
authors: Toshiyuki
authors: T
authors: Kudo
authors: Sumio
authors: S
authors: Takahashi
authors: Sakae
authors: S
authors: Takeuchi
mesh_terms: D017398:Alternative Splicing / Q000235:genetics; D000818:Animals; D015153:Blotting, Western; D005260:Female; D007150:Immunohistochemistry; D017403:In Situ Hybridization; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D051381:Rats; D017207:Rats, Sprague-Dawley; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013087:Spermatids / Q000378:metabolism; D013090:Spermatocytes / Q000378:metabolism; D013091:Spermatogenesis / Q000235:genetics / Q000502:physiology*; D013737:Testis / Q000378:metabolism*; D050817:Transcription Factor Pit-1 / Q000235:genetics / Q000378:metabolism*
chemical_list: D050817:Transcription Factor Pit-1