Myf5-/- :MyoD-/- amyogenic fetuses reveal the importance of early contraction and static loading by striated muscle in mouse skeletogenesis.
The mechanical loading of striated muscle is thought to play an important role in shaping bones and joints. Here, we examine skeletogenesis in late embryogenesis (embryonic day 18.5) in Myf5-/-:MyoD-/- fetuses completely lacking striated muscle. The phenotype includes enlarged and fused cervical vertebrae and postural anomalies, some viscerocranial anomalies, long bone truncation and fusion, absent deltoid tuberosity of the humerus, scapular and clavicular hypoplasia, cleft palate, and cleft sternum. In contrast, neurocranial bone development was essentially normal. While the magnitude of individual effects varied throughout the skeletal system, the results are consistent with skeletal development depending on functional muscles. Novel abnormalities in the amyogenic fetuses relative to less severely paralyzed phenotypes extend our understanding of skeletogenic dependence on embryonic muscle contraction and static loading.
Rot-Nikcevic
Irena
I
Department of Anatomy and Neurobiology, Faculty of Medicine, Dalhousie University, 5850 College Street, Halifax, NS, Canada, B3H 1X5.
Reddy
Tyler
T
Downing
Kevin J
KJ
Belliveau
Anne C
AC
Hallgrímsson
Benedikt
B
Hall
Brian K
BK
Kablar
Boris
B
D000818:Animals; D001842:Bone and Bones / Q000002:abnormalities / Q000196:embryology*; D005333:Fetus; D051379:Mice; D018345:Mice, Knockout; D009119:Muscle Contraction / Q000235:genetics*; D018482:Muscle, Skeletal / Q000196:embryology* / Q000502:physiology; D017570:MyoD Protein / Q000235:genetics* / Q000502:physiology; D051787:Myogenic Regulatory Factor 5 / Q000172:deficiency / Q000235:genetics* / Q000502:physiology; D010012:Osteogenesis / Q000235:genetics*
C497418:Myf5 protein, mouse; D017570:MyoD Protein; C057363:MyoD1 myogenic differentiation protein; D051787:Myogenic Regulatory Factor 5