Modulation of utrophin A mRNA stability in fast versus slow muscles via an AU-rich element and calcineurin signaling.
We examined the role of post-transcriptional mechanisms in controlling utrophin A mRNA expression in slow versus fast skeletal muscles. First, we determined that the half-life of utrophin A mRNA is significantly shorter in the presence of proteins isolated from fast muscles. Direct plasmid injection experiments using reporter constructs containing the full-length or truncated variants of the utrophin 3'UTR into slow soleus and fast extensor digitorum longus muscles revealed that a region of 265 nucleotides is sufficient to confer lower levels of reporter mRNA in fast muscles. Further analysis of this region uncovered a conserved AU-rich element (ARE) that suppresses expression of reporter mRNAs in cultured muscle cells. Moreover, stability of reporter mRNAs fused to the utrophin full-length 3'UTR was lower in the presence of fast muscle protein extracts. This destabilization effect seen in vivo was lost upon deletion of the conserved ARE. Finally, we observed that calcineurin signaling affects utrophin A mRNA stability through the conserved ARE. These results indicate that ARE-mediated mRNA decay is a key mechanism that regulates expression of utrophin A mRNA in slow muscle fibers. This is the first demonstration of ARE-mediated mRNA decay regulating the expression of a gene associated with the slow myogenic program.
Chakkalakal
Joe V
JV
Department of Cellular and Molecular Medicine and Centre for Neuromuscular Disease, Faculty of Medicine, University of Ottawa, Ottawa, ON, Canada.
Miura
Pedro
P
Bélanger
Guy
G
Michel
Robin N
RN
Jasmin
Bernard J
BJ
D020413:3' Untranslated Regions / Q000737:chemistry*; D000241:Adenosine / Q000032:analysis; D000818:Animals; D001483:Base Sequence; D019703:Calcineurin / Q000378:metabolism*; D002460:Cell Line; D017124:Conserved Sequence; D005786:Gene Expression Regulation; D017930:Genes, Reporter; D051379:Mice; D008810:Mice, Inbred C57BL; D018656:Muscle Fibers, Fast-Twitch / Q000378:metabolism*; D018657:Muscle Fibers, Slow-Twitch / Q000378:metabolism*; D018482:Muscle, Skeletal / Q000378:metabolism; D020871:RNA Stability; D012333:RNA, Messenger / Q000378:metabolism; D038621:Regulatory Sequences, Ribonucleic Acid; D015398:Signal Transduction; D014529:Uridine / Q000032:analysis; D049411:Utrophin / Q000235:genetics* / Q000378:metabolism
D020413:3' Untranslated Regions; D012333:RNA, Messenger; D038621:Regulatory Sequences, Ribonucleic Acid; C483600:Utrn protein, mouse; D049411:Utrophin; D019703:Calcineurin; D000241:Adenosine; D014529:Uridine