Epigenetic Modulation of Gene Expression in Developmentally Staged Gonadotrope Cell Lines

Program: Abstracts - Orals, Featured Poster Presentations, and Posters
Session: SAT 164-196-Pituitary
Saturday, June 15, 2013: 1:45 PM-3:45 PM
Expo Halls ABC (Moscone Center)

Poster Board SAT-190
Huimin Xie*1, Anita Kamalnath Iyer2 and Cindy Ngo3
1UCSD, San Diego, CA, 2UC San Diego, La Jolla, CA, 3UCSD
Gene regulation is controlled, not only by a highly orchestrated cascade of transcription factors, but also by epigenetic mechanisms that include the modulation of chromatin structure and histone modifications. Gene activation and repression are specifically regulated through changes in chromatin structure imparted mainly by histone modifications and DNA methylation. The developmentally staged gonadotrope cell lines, precursor αT1-1, immature αT3-1, and mature LβT2, are useful cell models to address the epigenetic regulation status of gonadotrope-specific genes (αGSU, GnRHR, FSHβ, and LHβ) during gonadotrope maturation. Since mature LβT2 cells induce FSHβ and LHβ after GnRH and/or activin treatment, epigenetic changes by hormone treatment have also been observed. Using DNaseI sensitivity assays, three classes of chromatin structure have been described: active, poised, and repressed. ChIP assays were performed to analyze histone modifications of all four genes during gonadotrope maturation assessing markers of active chromatin, Histone H3 acetylation (H3-Ac), H3K4 trimethylation (H3K4-Me3), RNA Polymerase II (RNAPII), and Phospho-RNAPII (p-RNAPII) binding, as well as the inactive chromatin markers, H3K9-Me2 and H3K27Me3.  Bisulfide methylation was also used to identify the DNA methylation of gonadotrope-specific genes at different development stages and with hormone treatment. In addition to epigenetic regulation of gonadotrope-specific genes, we also examined the binding of specific transcription factors, such as SF1, Lhx3 and Pitx1/2, with their target genes during gonadotrope development.

Nothing to Disclose: HX, AKI, CN

*Please take note of The Endocrine Society's News Embargo Policy at http://www.endo-society.org/endo2013/media.cfm

Sources of Research Support: NIH R01 HD020377, U54 HD012303, R01 DK044838, R01 HD-72754, T32 DK007044, T32 HD007203, F32 HD070579, F32 HD058427, T32 DK007494