Differential expression of laminin chains in hepatic lipocytes.
The lipocyte is an important source of laminin in the normal liver. We have investigated the expression of the 3 chains of laminin in isolated rat lipocytes. Both B1 and B2 chains, but not A, were found in medium from 5-day-old lipocyte primary cultures by immunoblotting and immunoprecipitation of 35S-labeled proteins after reducing SDS-polyacrylamide gel electrophoresis. An additional polypeptide of Mr = 380,000 was identified by immunoprecipitation. Under non-reducing conditions only one Mr = 900,000 band was revealed. High levels of B1 and B2 mRNAs were also demonstrated in 5-day-old cultured lipocytes while at the time of seeding, only B2 chain mRNAs were clearly detectable. A chain mRNA was constantly absent. These results suggest that lipocytes produce a variant form of laminin in primary culture and that the Mr = 380,000 polypeptide could be unrelated to the A chain of laminin.
Unité de Recherches Hépatologiques U 49 de l'INSERM, Hôpital de Pontchaillou, Rennes, France.
O
O
Loreal
F
F
Levavasseur
P Y
PY
Rescan
Y
Y
Yamada
A
A
Guillouzo
B
B
Clement
D000273:Adipose Tissue / Q000166:cytology / Q000502:physiology*; D000818:Animals; D015152:Blotting, Northern; D015153:Blotting, Western; D015870:Gene Expression; D007797:Laminin / Q000235:genetics / Q000378:metabolism*; D008099:Liver / Q000166:cytology / Q000502:physiology*; D012333:RNA, Messenger / Q000235:genetics; D051381:Rats; D011919:Rats, Inbred Strains
D007797:Laminin; D012333:RNA, Messenger