The human lumican gene. Organization, chromosomal location, and expression in articular cartilage.
A human lumican cDNA sequence was derived by polymerase chain reaction techniques from RNA obtained from intestine, placenta, and articular cartilage. A contiguous sequence of 1729 bases was obtained corresponding to an observed message size of 1.8 kilobases (kb). The cDNA sequence consists of an 80-base pair (bp) 5'-untranslated region, a 1014-bp coding sequence, and a 618-bp 3'-untranslated region terminating in a 17-bp poly(A) tail. The deduced lumican protein sequence has 338 amino acids, including a putative 18-residue signal peptide. The human lumican gene was shown to be spread over about 7.5 kb of genomic DNA and to be located on chromosome 12q22. The gene consists of 3 exons separated by introns of 2.2 and 3.5 kb. The shorter 5'-intron resides 21 bases prior to the translation initiation codon, and the 3'-intron resides 152 bases prior to the translation termination codon. The lumican message is expressed at high levels in adult articular chondrocytes but at low levels in the young juvenile. This age-related trend in message level is not, however, common to all tissues in which the lumican gene is expressed. Lumican is present in the extracellular matrix of human articular cartilage at all ages, although its abundance is far greater in the adult. In the adult cartilage lumican exists predominantly in a glycoprotein form lacking keratan sulfate, whereas the juvenile form of the molecule is a proteoglycan.
Grover
J
J
Genetics Unit, Shriners Hospital for Crippled Children, Montreal, Quebec, Canada.
Chen
X N
XN
Korenberg
J R
JR
Roughley
P J
PJ
D000368:Aged; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002358:Cartilage, Articular / Q000378:metabolism*; D002417:Cattle; D002645:Chickens; D011508:Chondroitin Sulfate Proteoglycans / Q000096:biosynthesis* / Q000235:genetics*; D002871:Chromosome Banding; D002874:Chromosome Mapping; D002881:Chromosomes, Human, Pair 12; D003062:Codon; D004247:DNA / Q000235:genetics / Q000378:metabolism; D017931:DNA Primers; D018076:DNA, Complementary; D015870:Gene Expression; D015186:Hominidae / Q000235:genetics*; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D007231:Infant, Newborn; D007438:Introns; D007632:Keratan Sulfate / Q000096:biosynthesis* / Q000235:genetics*; D000071234:Lumican; D008969:Molecular Sequence Data; D016133:Polymerase Chain Reaction; D017386:Sequence Homology, Amino Acid
D011508:Chondroitin Sulfate Proteoglycans; D003062:Codon; D017931:DNA Primers; D018076:DNA, Complementary; C000604306:LUM protein, human; D000071234:Lumican; D004247:DNA; D007632:Keratan Sulfate