Expression of laminin subunits in human fetal skeletal muscle

The laminin variant of adult skeletal muscle fibres and Schwann cells is known as merosin, and is composed of M-B1-B2 chains. Blood vessels and immature fibres express the A chain in association with B1 or S, and B2. The importance of merosin has recently been shown by its absence in one form of con...

Full description

Saved in:
Bibliographic Details
Published in:The Histochemical journal 1995-07, Vol.27 (7), p.497-504
Main Authors: Sewry, C A, Chevallay, M, Tomé, F M
Format: Article
Language:English
Subjects:
Embryonic and Fetal Development
Female
Humans
Immunohistochemistry
Laminin - biosynthesis
Laminin - chemistry
Muscle, Skeletal - embryology
Muscle, Skeletal - metabolism
Organ Specificity
Pregnancy
Terminology as Topic
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:The laminin variant of adult skeletal muscle fibres and Schwann cells is known as merosin, and is composed of M-B1-B2 chains. Blood vessels and immature fibres express the A chain in association with B1 or S, and B2. The importance of merosin has recently been shown by its absence in one form of congenital muscular dystrophy and in the mutant dy/dy mouse, and by its partial deficiency in Fukuyama congenital muscular dystrophy. We have examined the immunocytochemical localization of the M, A, B1 and B2 laminin chains in human fetal muscle from 7 to 40 weeks' gestation to ascertain their developmental expression. The B1 and B2 chains were detected on muscle fibres at 7 weeks, but only traces of the A or M chain were seen. By 21 weeks maximal levels of all four subunits were observed on all fibres. This suggests that the basement membrane is still being assembled until this stage of development. Expression of the A chain on muscle fibres was not reduced until 34 weeks and low levels persisted at birth. The concomitant expression of the M and A chains at early stages may indicate a laminin variant, in addition to merosin, that is highly expressed in fetal muscle. Merosin was seen in intramuscular nerves at 11 weeks. B1 and B2 subunits were detected in blood vessels from 7 weeks' gestation and the A chain from 11 weeks. The capillary network, however, is not fully established in fetal muscle. Merosin is therefore detected early during human fetal muscle development, and this should be taken into account when assessing aborted fetuses at risk for congenital muscular dystrophy.
ISSN:0018-2214
1573-6865
DOI:10.1007/BF02388749