Cy. Liu et al., THE CLONING OF MOUSE KERATOCAN CDNA AND GENOMIC DNA AND THE CHARACTERIZATION OF ITS EXPRESSION DURING EYE DEVELOPMENT, The Journal of biological chemistry, 273(35), 1998, pp. 22584-22588
Keratan sulfate proteoglycans (KSPGs) play a pivotal role in the devel
opment and maintenance of corneal transparency. Keratocan, lumican, an
d mimecan (osteoglycin) are the major KSPGs in vertebrate corneas. To
provide a better understanding of the structure/function relationship
of keratocan, we have cloned both the mouse keratocan gene and its cDN
A. We have also examined its expression during embryonic development.
The mouse keratocan gene spans approximately 6.5 kilobases of the mous
e genome and contains three exons and two introns. Northern blotting a
nd in situ hybridization were employed to examine keratocan gene expre
ssion during mouse development. Unlike lumican gene, which is expresse
d by many tissues other than cornea, keratocan mRNA is more selectivel
y expressed in the corneal tissue of the adult mouse. During embryonic
development, keratocan mRNA was first detected in periocular mesenchy
mal cells migrating toward developing corneas on embryonic day 13.5 (E
13.5). Its expression was gradually restricted to corneal stromal cell
s on E14.5 similar to E18.5. Interestingly, keratocan mRNA can be dete
cted in scleral cells of E15.5 embryos, but not in E18.5 embryos. In a
dult eyes, keratocan mRNA can be detected in corneal keratocytes, but
not in scleral cells.