Lui V C, Kong R Y, Nicholls J, Cheung A N, Cheah K S
Department of Biochemistry, University of Hong Kong, Hong Kong.
Biochem J. 1995 Oct 15;311 ( Pt 2)(Pt 2):511-6. doi: 10.1042/bj3110511.
In cartilage collagen type XI exists as heterotrimeric molecules composed of alpha 1(XI), alpha 2(XI) and alpha 3(XI) subunits. Messenger RNAs for some of the alpha chains of collagen type XI have also been found in non-chondrogenic tissues but the chain composition of the molecule in these sites is not known. Some non-chondrogenic tissues also contain heterotrimers containing collagen alpha 2(V) and alpha 1(XI) chains. We have explored the possibility that collagen type XI could exist in differing trimeric forms in non-chondrogenic tissues and aimed to predict the subunit composition of this collagen in those tissues. The distribution and relative levels of expression of collagen alpha 1(XI), alpha 2(XI) and alpha 3(XI)/alpha 1(II) mRNAs in different human fetal tissues were studied. Expression of mRNAs for all three genes of collagen type XI is not restricted to cartilage but is widespread. However, in some non-chondrogenic tissues, the mRNAs for all three alpha chains of collagen type XI were not co-expressed, but collagen alpha 1(XI) and alpha 2(XI) mRNAs were found either singly or without collagen alpha 3(XI) transcripts. Collagen type XI may therefore exist as homotrimers and/or heterotrimers composed of two collagen alpha(XI) chains in some tissues. The distribution of mRNAs for collagen alpha 2(V) and alpha 1(I) were also studied. Co-expression of collagen type XI, alpha 2(V) and alpha 1(I) mRNAs was found for many tissues. These findings have implications for the possibility of additional chain associations for collagen types XI and V in cross-type heterotrimers within heterotypic fibrils.
在软骨中，XI型胶原以由α1(XI)、α2(XI)和α3(XI)亚基组成的异源三聚体分子形式存在。在非软骨生成组织中也发现了XI型胶原一些α链的信使核糖核酸，但这些部位该分子的链组成尚不清楚。一些非软骨生成组织还含有包含胶原α2(V)和α1(XI)链的异源三聚体。我们探讨了XI型胶原在非软骨生成组织中可能以不同三聚体形式存在的可能性，并旨在预测该组织中这种胶原的亚基组成。研究了人胎儿不同组织中胶原α1(XI)、α2(XI)和α3(XI)/α1(II)信使核糖核酸的分布及相对表达水平。XI型胶原所有三个基因的信使核糖核酸表达并不局限于软骨，而是广泛存在。然而，在一些非软骨生成组织中，XI型胶原所有三个α链的信使核糖核酸并非共表达，而是发现胶原α1(XI)和α2(XI)信使核糖核酸单独存在或没有胶原α3(XI)转录本。因此，在某些组织中，XI型胶原可能以由两条胶原α(XI)链组成的同型三聚体和/或异型三聚体形式存在。还研究了胶原α2(V)和α1(I)信使核糖核酸的分布。发现许多组织中XI型胶原、α2(V)和α1(I)信使核糖核酸共表达。这些发现对于XI型和V型胶原在异型原纤维内的交叉型异源三聚体中形成额外链关联的可能性具有重要意义。
