Isolation of CDNA and Genomic Clones Encoding Human Pro-alpha 1 (III) Collagen. Partial Characterization of the 3' End Region of the Gene

A cDNA library constructed from human fibroblast poly(A+) RNA was screened for the identification of chimeric molecules bearing collagen-specific sequences. Analysis of three of the resulting positive clones showed that they encoded for the COOH-terminal propeptide region of the human Type III collagen. In addition, three overlapping clones covering more than 21 kilobases of the Type III gene were isolated from Charon 4A libraries of human genomic fragments. Identity between these and the cDNA clones was obtained by direct DNA sequencing. Establishment of the exon/intron arrangement of the Type III gene was obtained by electron microscopic analysis in conjunction with sequencing of selected genomic regions. Sequence comparison with other collagen genes confirmed some evolutionary features of this important family of proteins. Finally, the collinearity of two mRNA transcripts with 3' noncoding region length polymorphism was established.