Related expression of MyoD and Myf5 with myosin heavy chain isoform types in bovine adult skeletal muscles.
Skeletal muscles are characterized as fast and slow muscles, according to the expression pattern of myosin heavy chain (MyHC) isoforms in the muscle fibers. To investigate the relationships between MyHC isoforms and myogenic regulatory factors (MRFs) including MyoD, Myf5, myogenin, and MRF4 in adult skeletal muscles, expressions of these MRFs in the ten muscles of three cows were analyzed by a semi-quantitative RT-PCR. The results showed that MyoD expression was significantly lower in the lingual muscles (TN), masseter (MS) and diaphragm (DP), which lack MyHC-2x (fast glycolytic) expression and abound with MyHC-slow (slow oxidative) and/or MyHC-2a (fast oxidative), than it was in the pectoralis (PP), psoas major (PM), longissimus thoracis (LT), spinnalis (SP), semitendinosus (ST), semimembranosus (SM), and biceps femoris (BF). In contrast, the Myf5 expression in TN, MS, and DP was significantly higher than in PM, LT, ST, SM, and BF. No significant difference was observed in myogenin and MRF4 expression among the muscles tested. The results suggest that MyoD and Myf5 influence the MyHC isoform expression, although the effects are not decisive in specifying the phenotypes of adult muscles.
Muroya
Susumu
S
Department of Animal Products, National Institute of Livestock and Grassland Science, Tsukuba Norin-Kenkyu-Danchi, Ibaraki, Japan. muros@affrc.go.jp
Nakajima
Ikuyo
I
Chikuni
Koichi
K
D000375:Aging; D000818:Animals; D002417:Cattle; D004268:DNA-Binding Proteins; D005786:Gene Expression Regulation; D018656:Muscle Fibers, Fast-Twitch / Q000378:metabolism; D018657:Muscle Fibers, Slow-Twitch / Q000378:metabolism; D009124:Muscle Proteins / Q000235:genetics*; D018482:Muscle, Skeletal / Q000378:metabolism*; D017570:MyoD Protein / Q000235:genetics*; D051787:Myogenic Regulatory Factor 5; D018006:Myogenic Regulatory Factors / Q000235:genetics; D018008:Myogenin / Q000235:genetics; D018995:Myosin Heavy Chains / Q000235:genetics*; D009928:Organ Specificity; D020033:Protein Isoforms / Q000235:genetics; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015534:Trans-Activators
D004268:DNA-Binding Proteins; D009124:Muscle Proteins; D017570:MyoD Protein; D051787:Myogenic Regulatory Factor 5; D018006:Myogenic Regulatory Factors; D018008:Myogenin; D020033:Protein Isoforms; D012333:RNA, Messenger; D015534:Trans-Activators; C063403:myogenic factor 6; D018995:Myosin Heavy Chains