Differential expression of two exons of the alpha 1(XI) collagen gene (Col11a1) in the mouse embryo

The amino terminal domain of collagen XI has a unique structure, which is b elieved to participate in the regulation of matrix assembly. Interestingly, several distinct isoforms of the amino terminal domain of alpha1(XI) and a lpha2(XI) collagen chains exist as a result of alternative splicing. Here w e report the analysis of the alternative splicing pattern of the mouse alph a1(XI) collagen gene (Col11a1). Like other vertebrate species, the mutually exclusive expression of exons 6A and 6B of Col11a1 results in the inclusio n in the alpha1 chain of either an acidic peptide (pI 3.14) or a basic pept ide (pl 11.66). Expression of these two exons was monitored in several tiss ues of the 16.5-day mouse embryo by in situ hybridization and immunohistoch emistry, with exon-specific cDNA probes and peptide-specific antibodies, re spectively. The results documented that isoforms containing the exon 6B-enc oded peptide accumulate predominantly in the vertebrae, skeletal muscles an d intestinal epithelium. By contrast, exon 6A products were found to be mos t abundant in the smooth muscle cells of the intestine, aorta and lung. The results using in situ hybridization confirmed those using immunohistochemi stry. Albeit correlative, the evidence suggests distinct contributions of t he two peptides to the differential assembly of tissue-specific matrices. ( C) 2001 Elsevier Science B.V./International Society of Matrix Biology. All rights reserved.