TY - JOUR
T1 - A non-canonical E-box within the MyoD core enhancer is necessary for circadian expression in skeletal muscle
AU - Zhang, Xiping
AU - Patel, Samir P.
AU - McCarthy, John J.
AU - Rabchevsky, Alexander G.
AU - Goldhamer, David J.
AU - Esser, Karyn A.
N1 - Funding Information:
The National Institutes of Health (R01AR055246 to K.A.E., R01AR44878 to D.J.G.). Funding for open access charge: NIH (R01AR055246).
PY - 2012/4
Y1 - 2012/4
N2 - The myogenic differentiation 1 (MyoD) gene is a master regulator of myogenesis. We previously reported that the expression of MyoD mRNA oscillates over 24h in skeletal muscle and that the circadian clock transcription factors, BMAL1 (brain and muscle ARNT-like 1) and CLOCK (circadian locomotor output cycles kaput), were bound to the core enhancer (CE) of the MyoD gene in vivo. In this study, we provide in vivo and in vitro evidence that the CE is necessary for circadian expression of MyoD in adult muscle. Gel shift assays identified a conserved non-canonical E-box within the CE that is bound by CLOCK and BMAL1. Functional analysis revealed that this E-box was required for full activation by BMAL1/CLOCK and for in vitro circadian oscillation. Expression profiling of muscle of CEloxP/loxP mice found approximately 1300 genes mis-expressed relative to wild-type. Based on the informatics results, we analyzed the respiratory function of mitochondria isolated from wild-type and CEloxP/loxP mice. These assays determined that State 5 respiration was significantly reduced in CEloxP/loxP muscle. The results of this work identify a novel element in the MyoD enhancer that confers circadian regulation to MyoD in skeletal muscle and suggest that loss of circadian regulation leads to changes in myogenic expression and downstream mitochondrial function.
AB - The myogenic differentiation 1 (MyoD) gene is a master regulator of myogenesis. We previously reported that the expression of MyoD mRNA oscillates over 24h in skeletal muscle and that the circadian clock transcription factors, BMAL1 (brain and muscle ARNT-like 1) and CLOCK (circadian locomotor output cycles kaput), were bound to the core enhancer (CE) of the MyoD gene in vivo. In this study, we provide in vivo and in vitro evidence that the CE is necessary for circadian expression of MyoD in adult muscle. Gel shift assays identified a conserved non-canonical E-box within the CE that is bound by CLOCK and BMAL1. Functional analysis revealed that this E-box was required for full activation by BMAL1/CLOCK and for in vitro circadian oscillation. Expression profiling of muscle of CEloxP/loxP mice found approximately 1300 genes mis-expressed relative to wild-type. Based on the informatics results, we analyzed the respiratory function of mitochondria isolated from wild-type and CEloxP/loxP mice. These assays determined that State 5 respiration was significantly reduced in CEloxP/loxP muscle. The results of this work identify a novel element in the MyoD enhancer that confers circadian regulation to MyoD in skeletal muscle and suggest that loss of circadian regulation leads to changes in myogenic expression and downstream mitochondrial function.
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U2 - 10.1093/nar/gkr1297
DO - 10.1093/nar/gkr1297
M3 - Article
C2 - 22210883
AN - SCOPUS:84860381405
SN - 0305-1048
VL - 40
SP - 3419
EP - 3430
JO - Nucleic Acids Research
JF - Nucleic Acids Research
IS - 8
ER -