The Functional Characterization of Wdr68 Regulation of Pax7 Activity in Myogenesis

Title: The Functional Characterization of Wdr68 Regulation of Pax7 Activity in Myogenesis
Authors: Jackson, Anna Francina
Date: 2010
Abstract: In response to tissue trauma, quiescent satellite cells in adult skeletal muscle undergo proliferative activation and migrate to the site of injury where they differentiate and fuse to mend and replace damaged myofibers. The tightly synchronized expression of myogenic regulatory factors plays a critical role in orchestrating the regenerative process. In recent studies, we identified the transcription factor Pax7 as able to recruit the Wdr5-Ash2L-MLL2 histone methyltransferase complex to the -57.5kb Myf5 enhancer and to activate Myf5 transcription. We also identified Wdr68 as a putative Pax7 binding protein. Wdr68 is a scaffold protein thought to integrate Shh signaling but about which very little is known. Therefore, we set out to characterize a role for Wdr68 with Pax7 in early myogenesis. The interaction of endogenous Pax7 and exogenous Wdr68 was validated by reciprocal co-immunoprecipitation and western blot analysis. Manipulation of Wdr68 levels in primary myoblasts followed by real-time PCR analysis of Pax7 target genes suggests that Wdr68 acts as a negative regulator of Pax7. It has been determined by ChIP experiments that Wdr68 does not bind chromatin at some known genomic Pax7 binding sites. In addition, Wdr68 appears not to function by regulating Pax7 nuclear localization. These experiments provide new insights into the molecular control of Pax7 function during regenerative myogenesis and emphasize its complexity.
CollectionTh├Ęses, 1910 - 2010 // Theses, 1910 - 2010
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