title: Grazing-induced changes in muscle microRNA-206 and -208b expression in association with myogenic gene expression in cattle.
abstract: To investigate the roles of microRNAs (miRNAs) in muscle type conversion, the effects of 4 months of grazing on the expression levels of miRNAs and mRNAs associated with skeletal muscle development were analyzed by quantitative RT-PCR using the Biceps femoris muscle of Japanese Shorthorn cattle. After 4 months of grazing, the expression of muscle fiber type-associated miR-208b was higher in the grazed cattle than in the housed. In concordance with the pattern in miR-208b expression, the expression of MyoD, a myogenic regulatory factor associated with the shifting of muscle property to the fast type, was lower in the grazed cattle after 4 months of grazing than in the housed cattle. In addition, the expression of MyHC-2x (a fast type) was higher in the housed cattle than in the grazed, after 4 months of grazing. During the grazing period, miR-206 expression decreased in the housed cattle, whereas expression in the grazed cattle did not change, but rather remained higher than that of the housed cattle even at 3 months after the grazing ended. These miRNAs including miR-206 persisting with muscles of grazed cattle may be associated with regulation of muscle gene expression during skeletal muscle adaptation to grazing.
authors.affiliation: Livestock Research Division, Fukui Livestock Experimental Station, Sakai, Japan.
authors.forename: Akihiko
authors.initials: A
authors.lastname: Horikawa
authors.affiliation: Field Science Center, School of Veterinary Medicine, Kitasato University, Yakumo, Japan.
authors.forename: Hideki
authors.initials: H
authors.lastname: Ogasawara
authors.affiliation: Field Science Center, School of Veterinary Medicine, Kitasato University, Yakumo, Japan.
authors.forename: Kaito
authors.initials: K
authors.lastname: Okada
authors.affiliation: Field Science Center, School of Veterinary Medicine, Kitasato University, Yakumo, Japan.
authors.forename: Misato
authors.initials: M
authors.lastname: Kobayashi
authors.affiliation: Animal Products Research Division, NARO Institute of Livestock and Grassland Science, Tsukuba, Japan.
authors.forename: Susumu
authors.initials: S
authors.lastname: Muroya
authors.affiliation: Field Science Center, School of Veterinary Medicine, Kitasato University, Yakumo, Japan.
authors.forename: Masayuki
authors.initials: M
authors.lastname: Hojito
mesh_terms: D000818:Animals; D002417:Cattle / Q000235:genetics* / Q000378:metabolism*; D015870:Gene Expression; D018507:Gene Expression Regulation, Developmental / Q000235:genetics*; D060434:Herbivory / Q000502:physiology*; D008297:Male; D035683:MicroRNAs / Q000235:genetics* / Q000378:metabolism / Q000502:physiology; D024510:Muscle Development / Q000235:genetics*; D018482:Muscle, Skeletal / Q000254:growth & development* / Q000378:metabolism; D017570:MyoD Protein / Q000235:genetics / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction
chemical_list: D035683:MicroRNAs; D017570:MyoD Protein
keywords: grazing; microRNA; muscle type; myogenic regulatory factors; myosin heavy chain isoform