Binding of Ricinus communis I lectin to developing dystrophic muscle in human fetus.
In previous studies it was shown that a D-galactose-specific lectin, Ricinus communis I (RCA I), does not bind to the plasma membrane of muscle fibres from patients with Duchenne muscular dystrophy (DMD) in contrast to normal muscle. We have now studied RCA I binding to the membranes of developing human fetal muscle in fetuses at 95% risk of DMD (n = 6) and normal controls (n = 5) with a developmental range of 12-20 weeks of gestation. The results were compared to the membrane appearance with conventional ultrastructure. Binding of RCA I to the muscle basement membrane was consistently strong from the early stages of myogenesis, such as in fusing myoblasts/myocytes. RCA I binding to the plasma membrane was weak but detectable in both DMD and normal fetuses at 12-14 weeks of gestation. Both the normal and diseased condition showed an increase of RCA I labelling of the muscle plasma membrane at 15-17 weeks and strong labelling at 18-20 weeks of gestation. No difference was observed in the RCA I localization of normal and diseased human fetal muscle plasma membrane. It is concluded that (a) the plasma membrane in developing fetal muscle undergoes a maturation process between 12 and 20 weeks gestational age leading to an increase in expression of RCA I binding carbohydrate moieties; and (b) that the absence of RCA I binding glycoprotein in mature DMD muscle plasma membrane reflects a change acquired during the course of disease.
Voit
T
T
Jerry Lewis Muscle Research Centre, Department of Paediatrics and Neonatal Medicine, Royal Postgraduate Medical School, Hammersmith Hospital, London, U.K.
Sewry
C A
CA
Dunn
M J
MJ
Dubowitz
V
V
D002462:Cell Membrane / Q000648:ultrastructure; D005314:Embryonic and Fetal Development; D005260:Female; D005315:Fetal Diseases / Q000196:embryology / Q000378:metabolism* / Q000473:pathology; D006801:Humans; D008854:Microscopy, Electron; D009132:Muscles / Q000196:embryology / Q000378:metabolism* / Q000648:ultrastructure; D009136:Muscular Dystrophies / Q000196:embryology / Q000378:metabolism* / Q000473:pathology; D011247:Pregnancy; D012276:Ricin / Q000378:metabolism*
D012276:Ricin