Intermingling versus clonal coherence during skeletal muscle development: mosaicism in eGFP/nLacZ-labeled mouse chimeras.
To study the relative contributions of clonal coherence vs. myoblast intermingling to the formation of mammalian skeletal muscles, enhanced green fluorescent protein (eGFP) and nLacZ labels were used to analyze neonatal and adult mouse embryo aggregation chimeras. The eGFP marker allowed us to estimate absolute levels of the eGFP transgenic parental contributions as well as variances of levels within a chimeric individual; nLacZ served as a counter-label in neonatal chimeras. In mature chimeric muscle, free intracellular diffusion of eGFP led to an averaging of the eGFP level in individual myofibers. Chimerism, i.e., differing eGFP levels, was evident between corresponding right and left muscles, between adjacent back, body wall, limb (shank, foot), and extraocular muscles and among myofibers within these muscles. Inhomogeneities in muscles far from their somitic origin indicated unbalanced sampling from small founder pools. The results obtained with adult eGFP<-->0 chimeras were corroborated by neonatal chimeras with complementary eGFP<-->nLacZ labels.
Eberhard
Daniel
D
Developmental Biology and Molecular Pathology, Bielefeld University, Bielefeld, Germany.
Jockusch
Harald
H
D000818:Animals; D002454:Cell Differentiation; D003720:Densitometry; D005121:Extremities; D049452:Green Fluorescent Proteins / Q000378:metabolism*; D006257:Head; D007091:Image Processing, Computer-Assisted; D007150:Immunohistochemistry; D007763:Lac Operon; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D009030:Mosaicism; D024510:Muscle Development; D018482:Muscle, Skeletal / Q000196:embryology*; D009132:Muscles / Q000502:physiology; D009141:Musculoskeletal System / Q000196:embryology*; D013997:Time Factors
C485184:enhanced green fluorescent protein; D049452:Green Fluorescent Proteins