Sequence, molecular properties, and chromosomal mapping of mouse lumican.
OBJECTIVE
Lumican is a major proteoglycan of vertebrate cornea. This study characterizes mouse lumican, its molecular form, cDNA sequence, and chromosomal localization.


METHODS
Lumican sequence was determined from cDNA clones selected from a mouse corneal cDNA expression library using a bovine lumican cDNA probe. Tissue expression and size of lumican mRNA were determined using Northern hybridization. Glycosidase digestion followed by Western blot analysis provided characterization of molecular properties of purified mouse corneal lumican. Chromosomal mapping of the lumican gene (Lcn) used Southern hybridization of a panel of genomic DNAs from an interspecific murine backcross.


RESULTS
Mouse lumican is a 338-amino acid protein with high-sequence identity to bovine and chicken lumican proteins. The N-terminus of the lumican protein contains consensus sequences for tyrosine sulfation. A 1.9-kb lumican mRNA is present in cornea and several other tissues. Antibody against bovine lumican reacted with recombinant mouse lumican expressed in Escherichia coli and also detected high molecular weight proteoglycans in extracts of mouse cornea. Keratanase digestion of corneal proteoglycans released lumican protein, demonstrating the presence of sulfated keratan sulfate chains on mouse corneal lumican in vivo. The lumican gene (Lcn) was mapped to the distal region of mouse chromosome 10. The Lcn map site is in the region of a previously identified developmental mutant, eye blebs, affecting corneal morphology.


CONCLUSIONS
This study demonstrates sulfated keratan sulfate proteoglycan in mouse cornea and describes the tools (antibodies and cDNA) necessary to investigate the functional role of this important corneal molecule using naturally occurring and induced mutants of the murine lumican gene.
Funderburgh
J L
JL
Division of Biology, Kansas State University, Manhattan 66506-4901, USA.
Funderburgh
M L
ML
Hevelone
N D
ND
Stech
M E
ME
Justice
M J
MJ
Liu
C Y
CY
Kao
W W
WW
Conrad
G W
GW
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002417:Cattle; D002645:Chickens; D011508:Chondroitin Sulfate Proteoglycans / Q000737:chemistry* / Q000235:genetics; D002874:Chromosome Mapping; D003001:Cloning, Molecular; D003315:Cornea / Q000737:chemistry*; D017931:DNA Primers / Q000737:chemistry; D015342:DNA Probes / Q000737:chemistry; D018076:DNA, Complementary / Q000032:analysis / Q000302:isolation & purification; D004926:Escherichia coli / Q000235:genetics; D005136:Eye Proteins / Q000737:chemistry* / Q000235:genetics; D005260:Female; D015870:Gene Expression; D007632:Keratan Sulfate / Q000737:chemistry* / Q000235:genetics; D000071234:Lumican; D008297:Male; D051379:Mice; D008969:Molecular Sequence Data; D011994:Recombinant Proteins
D011508:Chondroitin Sulfate Proteoglycans; D017931:DNA Primers; D015342:DNA Probes; D018076:DNA, Complementary; D005136:Eye Proteins; C000604307:Lum protein, mouse; D000071234:Lumican; D011994:Recombinant Proteins; D007632:Keratan Sulfate