Expression of nuclear lamin A and muscle-specific proteins in differentiating muscle cells in ovo and in vitro.
Primary cultures and tissue samples of chicken embryonic muscle were immunologically probed for the expression of muscle-specific proteins, such as myosin heavy chain and the tropomyosins, as well as for the nuclear lamina protein, lamin A. As determined by quantitative immunoblotting, the expression of lamin A and the muscle-specific proteins were at low levels or absent in predifferentiation myoblasts both in vitro and in ovo. During differentiation, an increase of lamin A expression preceded the induction to high levels of expression of muscle-specific proteins. Immunofluorescence staining of chicken embryonic muscle cells in culture also indicates an accumulation of lamin A before the induction of muscle-specific proteins expression. Furthermore, the accumulation of lamin A reached a plateau before the muscle-specific proteins during muscle development. In two dimensional NEPHGE gel analysis of immunoprecipitated lamin A, no detectable change in the ratio of the acidic/basic isoelectric variants of lamin A was observed during myogenesis. A potential role for lamin A in the mechanisms which underlie the differential and coordinate expression of muscle-specific genes is proposed.
Lourim
D
D
Department of Biology, University of Iowa, Iowa City 52242.
Lin
J J
JJ
D000818:Animals; D002454:Cell Differentiation; D002642:Chick Embryo; D005455:Fluorescent Antibody Technique; D015151:Immunoblotting; D034904:Lamin Type A; D034882:Lamins; D009124:Muscle Proteins / Q000235:genetics; D009132:Muscles / Q000166:cytology* / Q000378:metabolism; D009218:Myosins / Q000235:genetics / Q000378:metabolism*; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism*; D011233:Precipitin Tests; D014335:Tropomyosin / Q000235:genetics / Q000378:metabolism*
D034904:Lamin Type A; D034882:Lamins; D009124:Muscle Proteins; D009687:Nuclear Proteins; D014335:Tropomyosin; D009218:Myosins