Identification and Characterization of TSSK6 Activating Co‐chaperone (TSACC) in Skeletal Muscle

Abstract

Skeletal muscle atrophy is a physiological condition that is caused by a variety of conditions, including immobilization, denervation, spinal cord injury and aging and results in decreased muscle size and strength. In order to better characterize the molecular genetic events of neurogenic atrophy, the gastrocnemius muscle was isolated from mice following 3 days and 14 days of sciatic nerve denervation. The gene expression profile in the denervated muscle tissue was then analyzed by microarray and compared to control muscle tissue in order to identify novel neurogenic atrophy‐induced genes. The microarray data revealed for the first time that TSSK6 Activating Co‐chaperone (TSACC) is expressed in skeletal muscle and is significantly induced in response to denervation. To confirm that TSACC is expressed in muscle cells, we cloned the predicted TSACC cDNA from muscle cells, as well as a novel TSACC splice variant that contains an additional exon. Furthermore, quantitative PCR (qPCR) was used to assess TSACC expression levels in both proliferating and differentiated muscle cells and the results demonstrate that TSACC expression levels are relatively low in proliferating myoblasts, but show significantly elevated expression in differentiated myotubes. In order to characterize the transcriptional regulation of TSACC, fragments of the proximal promoter located immediately upstream of the start of transcription were cloned and fused to a reporter gene. The reporter plasmids were then transfected into C2C12 mouse muscle cells in combination with myogenic regulatory factor (MRF) expression plasmids, which resulted in significant activation of reporter gene activity. Interestingly, there are several predicted MyoD binding elements in the proximal promoter region of the TSACC gene further suggesting that TSACC may be regulated by muscle specific transcription factors. The discovery that TSACC is induced in response to neurogenic atrophy helps further our understanding of the molecular genetic events of muscle atrophy and may eventually lead to the identification of new therapeutic targets for the treatment and prevention of muscle wasting.Support or Funding InformationThe 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.