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Characterization of the Regulation and Function of Tetratricopeptide 39c (Ttc39c) in Skeletal Muscle
Author(s) -
Hayes Caleb,
Waddell David
Publication year - 2018
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.2018.32.1_supplement.856.24
Subject(s) - myogenesis , biology , ectopic expression , transcriptional regulation , microbiology and biotechnology , reporter gene , gene isoform , ubiquitin ligase , myocyte , c2c12 , skeletal muscle , regulation of gene expression , ring finger , gene expression , gene , ubiquitin , genetics , endocrinology
Ttc39c has been identified as a novel gene in skeletal muscle that is differentially regulated in response to neurogenic atrophy in wild‐type (WT) mice compared to Muscle RING Finger 1 (MuRF1) knockout (KO) mice. MuRF1 is a ubiquitin E3 ligase that is known to be an important mediator of muscle wasting; however, more recent research suggests that MuRF1 may also function as a regulator of atrophy‐induced gene expression. Quantitative PCR and Western blot analysis determined that Ttc39c is expressed in both proliferating and differentiated muscle cells. Furthermore, comparison of Ttc39c expression in undifferentiated and differentiated C 2 C 12 cells demonstrated that Ttc39c levels are elevated in proliferating myoblasts, but decrease in differentiated myotubes. The transcriptional regulation of two Ttc39c isoforms with alternative transcriptional start sites were examined by cloning the unique promoter regions of each transcript. The Ttc39c reporter gene constructs were transfected into muscle cells and confirmed to have significant transcriptional activity in cultured muscle cells and are transcriptionally responsive to ectopic expression of myogenic regulatory factors (MRF). Furthermore, conserved E‐box elements in the proximal promoter regions of both Ttc39c transcripts were identified, mutated, and analyzed for their role in the transcriptional regulation of Ttc39c expression. The mutation of the conserved E‐box sequences rendered the Ttc39c reporter genes inactive, suggesting that these elements are potentially necessary for Ttc39c expression. Finally, immunoprecipitation (IP) of Ttc39c from C 2 C 12 cells resulted in the co‐IP of numerous binding partners, which are currently being identified by proteomic analysis in the hope of elucidating a potential function for Ttc39c in skeletal muscle based on identified binding partners. Interestingly, ectopic expression of Ttc39c in C 2 C 12 mouse myoblasts resulted in delayed cell fusion and reduction in myotube formation. The identification and characterization of novel genes that are activated during neurogenic atrophy helps improve our understanding of the molecular genetic events that result in muscle wasting and could eventually lead to new therapeutic targets in the future. Support or Funding Information The work was support by University of North Florida Transformational Learning Opportunity grants to D.W. This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal .