title: Masticatory (;superfast') myosin heavy chain and embryonic/atrial myosin light chain 1 in rodent jaw-closing muscles.
abstract: Masticatory myosin is widely expressed among several vertebrate classes. Generally, the expression of masticatory myosin has been associated with high bite force for a carnivorous feeding style (including capturing/restraining live prey), breaking down tough plant material and defensive biting in different species. Masticatory myosin expression in the largest mammalian order, Rodentia, has not been reported. Several members of Rodentia consume large numbers of tree nuts that are encased in very hard shells, presumably requiring large forces to access the nutmeat. We, therefore, tested whether some rodent species express masticatory myosin in jaw-closing muscles. Myosin isoform expression in six Sciuridae species was examined, using protein gel electrophoresis, immunoblotting, mass spectrometry and RNA analysis. The results indicate that masticatory myosin is expressed in some Sciuridae species but not in other closely related species with similar diets but having different nut-opening strategies. We also discovered that the myosin light chain 1 isoform associated with masticatory myosin heavy chain, in the same four Sciuridae species, is the embryonic/atrial isoform. We conclude that rodent speciation did not completely eliminate masticatory myosin and that its persistent expression in some rodent species might be related to not only diet but also to feeding style.
authors: Department of Oral Biology, The Ohio State University, Columbus, OH 43210, USA. reiser.17@osu.edu
authors: Peter J
authors: PJ
authors: Reiser
authors: Sabahattin
authors: S
authors: Bicer
authors: Qun
authors: Q
authors: Chen
authors: Ling
authors: L
authors: Zhu
authors: Ning
authors: N
authors: Quan
mesh_terms: D000818:Animals; D017931:DNA Primers; D004285:Dogs / Q000502:physiology; D004622:Embryo, Mammalian / Q000502:physiology; D005247:Feeding Behavior / Q000502:physiology; D005784:Gene Amplification; D007568:Jaw / Q000502:physiology*; D008410:Masticatory Muscles / Q000502:physiology*; D018482:Muscle, Skeletal / Q000502:physiology*; D018995:Myosin Heavy Chains / Q000032:analysis* / Q000235:genetics / Q000378:metabolism; D018994:Myosin Light Chains / Q000032:analysis* / Q000235:genetics / Q000378:metabolism; D009754:Nuts; D016133:Polymerase Chain Reaction / Q000379:methods; D012313:RNA / Q000235:genetics; D012333:RNA, Messenger / Q000235:genetics; D012377:Rodentia / Q000033:anatomy & histology / Q000235:genetics / Q000502:physiology*; D012589:Sciuridae / Q000033:anatomy & histology / Q000235:genetics / Q000502:physiology
chemical_list: D017931:DNA Primers; D018994:Myosin Light Chains; D012333:RNA, Messenger; D012313:RNA; D018995:Myosin Heavy Chains