THE GENE ORGANIZATION, CHROMOSOME LOCATION, AND EXPRESSION OF A 55-KDA MATRIX PROTEIN (PRELP) OF HUMAN ARTICULAR-CARTILAGE

The gene corresponding to a 55-kDa matrix protein previously described in adult human articular cartilage was characterized by sequencing of genomic clones. The deduced protein sequence corresponds to the recen tly described matrix protein PRELP. The protein was encoded by message s of 1.7, 4.6, and 6.7 kb, whose relative abundance increased as their size decreased. The message heterogeneity appears to originate from v ariation in the length of the S'-untranslated region, with the smalles t message being contained within the reported sequence and the larger messages having extended 3'-untranslated regions. Two introns were ide ntified within the genomic sequence encoding the smallest message. The first intron of about 6.7 kb resides 16 nucleotides prior to the tran slation initiation codon, and the second intron of about 2.6 kb reside s 173 nucleotides prior to the translation termination codon. The gene , which encompasses at least 16 kb of genomic DNA, was shown to reside on chromosome 1q32. Primer extension techniques were used to establis h that the coding sequence commences 199 bp downstream from the major transcription start site. Analysis of the DNA sequence upstream from t he transcription start site reveals the presence of numerous potential transcription factor binding sites, but no CAAT or TATA box. At the m essage level, gene expression was at a high level in juvenile and adul t cartilage, but not in the fetus or neonate. The presence of protein in the cartilage matrix was also much lower in the neonate than in the adult. In noncartilagenous tissues appreciable message levels were ob served only in the adult lung. (C) l996 Academic Press, Inc.