Information provided by the skeletal muscle and associated neurons is necessary for proper brain development.
Previously, motor cortex of term Myf5(-/-):MyoD(-/-) fetuses (e.g. have ablated skeletal myogenesis and consequent early loss of lower motor and proprioceptive neurons) was found to lack giant pyramidal cells. We further investigated how the absence of the extrinsic stimuli from the lacking structures influences brain development. Apparently normal motor cortex of mutant fetuses was found to have dramatically reduced presence of nestin-expressing processes of neural precursors, calretinin-expressing pyramidal neurons and calbindin-expressing neurons. Consistently, some areas of the extrapyramidal tract had significantly decreased number of differentiated neurons in mutant brains. Surprisingly, we were unable to detect any change in proliferation or cell death in the mutant neuroepithelium. Together, it appears that the information provided by the lacking structures influences the ratios of the differentiated neuronal types and their progenitor cells.
Kablar
Boris
B
Department of Anatomy and Neurobiology, Dalhousie University, 5859 University Avenue, Halifax, NS, Canada B3H 4H7. bkablar@is.dal.ca
Rudnicki
Michael A
MA
D000818:Animals; D001921:Brain / Q000002:abnormalities* / Q000196:embryology / Q000378:metabolism / Q000473:pathology*; D002454:Cell Differentiation; D002460:Cell Line; D004268:DNA-Binding Proteins; D005314:Embryonic and Fetal Development; D051379:Mice; D008818:Mice, Neurologic Mutants; D009124:Muscle Proteins / Q000172:deficiency*; D018482:Muscle, Skeletal / Q000002:abnormalities* / Q000196:embryology / Q000254:growth & development; D017570:MyoD Protein / Q000378:metabolism*; D051787:Myogenic Regulatory Factor 5; D009474:Neurons / Q000378:metabolism / Q000473:pathology*; D012016:Reference Values; D015398:Signal Transduction; D015534:Trans-Activators
D004268:DNA-Binding Proteins; D009124:Muscle Proteins; C497418:Myf5 protein, mouse; D017570:MyoD Protein; D051787:Myogenic Regulatory Factor 5; D015534:Trans-Activators