Fassler R, Schnegelsberg PN, Dausman J, Shinya T, Muragaki Y, McCarthy MT, Olsen BR, Jaenisch R:
Mice lacking alpha 1 (IX) collagen develop noninflammatory
degenerative joint disease.
Proceedings of the National Academy of Sciences of the United States of
America 1994 May 24;91(11):5070-4
ABSTRACT
Type IX collagen is a nonfibrillar collagen composed of three gene
products, alpha 1(IX), alpha 2(IX), and alpha 3(IX). Type IX
molecules are localized on the surface of type II-containing fibrils
and consist of two arms, a long arm that is crosslinked to type II
collagen and a short arm that projects into the perifibrillar space.
In hyaline cartilage, the alpha 1(IX) collagen transcript encodes a
polypeptide with a large N-terminal globular domain (NC4), whereas
in many other tissues an alternative transcript encodes an alpha
1(IX) chain with a truncated NC4 domain. It has been proposed that
type IX molecules are involved in the interaction of fibrils with
each other or with other components of the extracellular matrix. To
test this hypothesis, we have generated a mouse strain lacking both
isoforms of the alpha 1(IX) chain. Homozygous mutant mice are viable
and show no detectable abnormalities at birth but develop a severe
degenerative joint disease resembling human osteoarthritis.
