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Differential abilities of the chicken Pit‐1 isoforms to regulate the chicken growth hormone promoter
Author(s) -
Mukherjee Malini,
Porter Tom Eric
Publication year - 2011
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.25.1_supplement.850.6
Subject(s) - gene isoform , transactivation , biology , transcription factor , prolactin , promoter , gene , transfection , transcription (linguistics) , microbiology and biotechnology , reporter gene , gene expression , endocrinology , hormone , medicine , genetics , linguistics , philosophy
Pit‐1 is a pituitary‐specific transcription factor expressed in three cell types of the anterior pituitary gland that regulates transcription of the peptide hormones prolactin, thyroid‐stimulating hormone β‐subunit and growth hormone (GH). In chickens, four Pit‐1 isoform mRNAs, Pit‐1α, Pit‐1β1, Pit‐1β2 and Pit‐1γ, have been identified, which differ from each other in their N‐terminal transactivation domains. Based on these differences, we hypothesized that the isoforms will differ in their ability to regulate transcription. Our study aimed to characterize the ability of each isoform to regulate the chicken GH gene. Chicken LMH cells were transfected with expression vectors for each isoform, along with a luciferase reporter construct driven by 1727bp of the 5′‐flanking region of the GH gene. We found that Pit‐1α, Pit‐1β1 and Pit‐1β2 activated the chicken GH promoter (P<0.05, n= 4 replicates), while Pit‐1γ had no effect. From our results, we conclude that Pit‐1β1 is the most efficient among all the isoforms in activating the chicken GH promoter. Future work will focus on the ability of the isoforms to interact with other transcriptional activators and to bind to Pit‐1 binding sites on the chicken GH promoter, as potential mechanisms behind the differences in transactivational properties. Supported by Grant no. 2009‐35206‐05189 from the USDA National Institute of Food and Agriculture.