title: Loss of synaptic vesicles from neuromuscular junctions in aged MRF4-null mice.
abstract: MRF4 belongs to the basic helix-loop-helix class of transcription factors and this and other members of its family profoundly influence skeletal muscle development. Less is known about the role of these factors in aging. As MRF4 is preferentially expressed in subsynaptic nuclei, we postulated it might play a role in maintenance of the neuromuscular junction. To test this hypothesis, we examined the junctional regions of 19-20-month-old mice and found decreased levels of SV2B, a marker of synaptic vesicles, in MRF4-null mice relative to controls. There was a corresponding decrease in grip strength in MRF4-null mice. Taken together, these data suggest that the intrinsic muscle factor, MRF4 plays an important role in maintenance of neuromuscular junctions.
authors.affiliation: Department of Neuroscience, Cell Biology, and Physiology, Wright State University School of Medicine, Dayton, Ohio 45435, USA.
authors.forename: Qingbo
authors.initials: Q
authors.lastname: Wang
authors.forename: Sadie L
authors.initials: SL
authors.lastname: Hebert
authors.forename: Mark M
authors.initials: MM
authors.lastname: Rich
authors.forename: Susan D
authors.initials: SD
authors.lastname: Kraner
mesh_terms: D000375:Aging / Q000235:genetics / Q000378:metabolism* / Q000473:pathology*; D000818:Animals; D004195:Disease Models, Animal; D005260:Female; D051379:Mice; D018345:Mice, Knockout; D018908:Muscle Weakness / Q000235:genetics / Q000378:metabolism* / Q000473:pathology*; D018482:Muscle, Skeletal / Q000294:innervation / Q000473:pathology* / Q000503:physiopathology; D018006:Myogenic Regulatory Factors / Q000235:genetics* / Q000502:physiology; D009469:Neuromuscular Junction / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D013572:Synaptic Vesicles / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D014157:Transcription Factors / Q000172:deficiency / Q000235:genetics
chemical_list: D018006:Myogenic Regulatory Factors; D014157:Transcription Factors; C063403:myogenic factor 6