Meeting Abstract

99.7  Monday, Jan. 6 15:00  EPIGENETIC REGULATION OF INDETERMINATE MYOGENESIS: Characterization of histone modifications during the myogenic program in rainbow trout, Oncorhynchus mykiss FROEHLICH, J.M.*; SEILIEZ, I.; GABILLARD, J.C.; BIGA, P.R.; University of Alabama at Birmingham; Institut National de la Recherche Agronomique, UR1067 Nutrition Métabolisme Aquaculture; INRA, UR1037 Station Commune de Recherches en Ichtyophysiologie Biodiversité et Environnement SCRIBE; University of Alabama at Birmingham jmfroehlich@uab.edu

While fish biologists have recognized for many decades that most teleost fishes grow under a paradigm divergent from that of terrestrial vertebrates, including mammals, the exact underpinnings of the molecular program governing such growth remain elusive. To better understand the protein-to-DNA interactions regulating two genes known to play pivotal roles in myogenesis among vertebrates, Pax7 during quiescence, proliferation, and self-renewal; and myogenin during terminal differentiation and myotube formation, we profiled the accessibility of chromatin in MPCs, myoblasts, and myotubes isolated from rainbow trout (Oncorhynchus mykiss) at the histone H3 using chromatin immunoprecipitation (ChIP) assays based on trimethylation marks at three key lysine residues: K4, K9, and K27. Quantitative PCR of chromatin fragments, enriched for each of these methylated lysine residues, revealed differential regulation of the promoter for Pax7 at Polycomb (PcG) and trithorax (trxG) group binding sites. Similarly, the myogenin promoter appeared to be regulated in a cell stage-specific manner near the transcriptional start site (TSS). With increasing research interest in histone methyltransferase and demethylase enzymes, these descriptive data reveal potential targets for growth modulation in important food fish species, including the ever-important salmonids modeled here.