TYPE-XIV COLLAGEN IS ENCODED BY ALTERNATIVE TRANSCRIPTS WITH DISTINCT5' REGIONS AND IS A MULTIDOMAIN PROTEIN WITH HOMOLOGIES TO VONWILLEBRAND-FACTOR, FIBRONECTIN, AND OTHER MATRIX PROTEINS

The combined nucleotide sequences of several overlapping cDNAs provide the first complete amino acid sequence of type XIV collagen. Independ ent confirmation of the deduced sequence is provided by amino acid seq uencing of several tryptic peptides isolated from purified chicken ski n type XIV collagen. Comparative analyses show that the amino-terminal nontriple-helical region of alpha1(XIV) chains contains sequence moti fs that are similar to alpha1(IX) collagen, fibronectin type III repea ts, and von Willebrand's factor A-domains. The results also strongly s uggest that the alpha1(XIV) collagen gene is identical to the gene enc oding the matrix component previously named undulin. cDNAs covering th e 5' region of alpha1(XIV) mRNA fall into two classes with distinct se quences in their 5'-untranslated regions. We believe the two alternati ve sequences result from differential splicing of the primary transcri pt. Interestingly, one of the untranslated sequences shows a high degr ee of identity with the cis-regulatory translational control sequence in the 5'-untranslated region of a Drosophila ribosomal protein mRNA. We hypothesize therefore that the sequence in alpha1(XIV) collagen may play a role in the control of alpha1(XIV) protein synthesis.