Primary structure and expression of a chicken laminin beta chain: evidence for four beta chains in birds.
Characterization of a full length cDNA sequence for a chicken laminin beta chain is described which is most closely related to the mammalian beta 2 chain. Comparison with published sequences shows that the chicken beta 2-like chain corresponds to a fragment of a previously described laminin beta chain called B1-2 (O'Rear, 1992). The sequence of the chicken beta 2-like chain differed from fragments of two other chicken laminin beta chains that were previously described and designated B1-1 (now called beta 1; O'Rear, 1992) and beta x (Ybot-Gonzalez et a1.,1995). In addition, the beta 2- like chain does not appear to be the chicken equivalent of the mammalian laminin beta 3 chain, since it differs markedly in cDNA sequence, possesses domain IV and has a transcript size of 6 kb. We therefore propose that there are at least four laminin beta chains in the chicken. Sequence comparison of the beta 2-like laminin chain with previously cloned beta 1 and beta 2 chains shows a somewhat closer relationship to rat and human beta 2 than to mouse and human beta 1, especially in domains I, II and alpha. In addition, two expressed fragments of the chicken beta 2-like chain were recognized by a monoclonal antibody (C4) regarded as specific for the rat beta 2 chain (Hunter et al., 1989a). The results therefore suggest that the laminin chain previously described as a potentially novel chain called B1-2 (O'Rear, 1992) is likely to be the chicken equivalent of the mammalian beta 2 chain.
Liu
J
J
Department of Cell Biology, University of Alabama at Birmingham 35294-0019, USA.
Swasdison
S
S
Xie
W
W
Brewton
R G
RG
Mayne
R
R
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D015152:Blotting, Northern; D002645:Chickens; D003001:Cloning, Molecular; D006801:Humans; D007797:Laminin / Q000096:biosynthesis* / Q000737:chemistry* / Q000235:genetics; D051379:Mice; D008969:Molecular Sequence Data; D018482:Muscle, Skeletal; D051381:Rats; D017386:Sequence Homology, Amino Acid
D007797:Laminin; C058783:laminin beta2