ISOLATED DYSTROPHIN MOLECULES AS SEEN BY ELECTRON-MICROSCOPY

被引:90
作者
PONS, F
AUGIER, N
HEILIG, R
LEGER, J
MORNET, D
LEGER, JJ
机构
[1] FAC PHARM MONTPELLIER,INSERM,U300,UNITE PATHOL MOLEC MUSCLE,AVE CHARLES FLAHAUT,F-34060 MONTPELLIER 1,FRANCE
[2] FAC MED MONTPELLIER,F-34000 MONTPELLIER,FRANCE
[3] CNRS,GENET MOLEC EUCARYOTES LAB,INSERM,U184,F-67085 STRASBOURG,FRANCE
关键词
actinin; chicken gizzard; smooth muscle; spectrin;
D O I
10.1073/pnas.87.20.7851
中图分类号
O [数理科学和化学]; P [天文学、地球科学]; Q [生物科学]; N [自然科学总论];
学科分类号
07 ; 0710 ; 09 ;
摘要
Dystrophin, the protein product of the Duchenne muscular dystrophy locus [Hoffman, E. P., Brown, R. H., Jr., and Kunkel, L. M. (1987) Cell 51, 919-928], is expressed in striated and smooth muscles as well as in non-muscle tissues. Examination of its primary structure has revealed that the molecule is composed of four domains, three of which share many features with the membrane cytoskeletal proteins spectrin and actinin. Dystrophin has thus been predicted to adopt a rod shape [Koenig, M., Monaco, A. P. and Kunkel, L. M. (1988) Cell 53, 219-228]. In the present study, we describe its isolation from the chicken gizzard smooth muscle and present electron microscopic images of the molecule. Polyclonal antibodies were first prepared from a dystrophin fragment derived from the chicken skeletal muscle gene (residues 1173-1728). A dystrophin-enriched membrane preparation from chicken gizzard muscle was then purified by passing it through an affinity chromatography column made with the anti-dystrophin antibodies. Electron microscopy of isolated and rotatory-shadowed dystrophin molecules revealed that the lengths measured for the dystrophin monomers (175 ± 15 nm) are compatible with a structural arrangement of the repeat sequence segments in triple-barrel α-helices connected by short-turn regions, as was earlier postulated for the repeat domains of spectrin and actinin. Electron microscopic images indicate that in addition the dystrophin molecules could present the same capacity of self-association in oligomeric structures as these cytoskeletal proteins and may thus be a part of a complex molecular meshwork essential to muscle cell function.
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页码:7851 / 7855
页数:5
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