Premium
Characterization of the Transcriptional Regulation of Tetratricopeptide Repeat Doman 39c (Ttc39c) in Skeletal Muscle
Author(s) -
Waddell David,
Menke Jacob
Publication year - 2015
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.29.1_supplement.880.20
Subject(s) - myogenesis , reporter gene , c2c12 , myogenin , biology , microbiology and biotechnology , ring finger , ubiquitin ligase , myocyte , gene , gene expression , transcriptional regulation , regulation of gene expression , muscle atrophy , skeletal muscle , ubiquitin , genetics , endocrinology
Ttc39c has been identified as a novel gene in skeletal muscle that is differentially regulated under conditions of neurogenic atrophy in wild‐type mice compared to Muscle RING Finger 1 (MuRF1) knockout mice. MuRF1 is a ubiquitin E3 ligase that is known to be an important mediator of muscle wasting; however, evidence presented here suggests that MuRF1 may also function as a regulator of atrophy‐induced gene expression. Western blot analysis comparing undifferentiated and differentiated C 2 C 12 cell lysates demonstrates that Ttc39c protein is expressed in proliferating myoblasts, but is reduced in differentiated myotubes. The transcriptional regulation of Ttc39c was examined by cloning the promoter region and fusing it to a reporter gene. This reporter construct was then transfected into muscle cells along with an expression plasmid for MuRF1. MuRF1 overexpression repressed Ttc39c reporter activity, while overexpression of a MuRF1 RING domain mutant failed to repress the Ttc39c reporter. Furthermore, overexpression of myogenin, which is a myogenic regulatory factor (MRF) that regulates the expression of muscle‐specific genes by binding to E‐box elements, also repressed Ttc39c reporter gene activity. A conserved E‐box element in the Ttc39c proximal promoter was identified, mutated and analyzed for its role in the regulation of Ttc39c expression. The mutation of the conserved E‐box rendered the Ttc39c reporter gene inactive, demonstrating that the element is necessary for Ttc39c expression. The identification and characterization of novel genes that are activated during neurogenic atrophy helps improve our understanding of the molecular genetic events that lead to muscle wasting and could eventually lead to new therapeutic targets in the future.