Nucleic Acids Research, 1983, Vol. 11, No. 9 2733-2744
© 1983
MOLECULAR BIOLOGY |
A conserved nucleotide sequence, coding for a segment of the C-propeptkle, is found at the same location in different collagen genes
Laboratory of Molecular Biology, National Cancer Institute, National Institutes of Health Bethesda, MD 20205, USA
Received January 13, 1983. Revised April 5, 1983. Accepted April 5, 1983.
The nucleotide sequence of a segment of the chick al type III collagen gene which codes for the C-propeptide was determined and compared with the corresponding sequence 1n the al type I and a2 type I collagen genes. As In the a2 type I gene the coding Information for the C-propeptide of the type III collagen gene 1s subdivided 1n four exons. Similarly, the amino proximal exon contains sequences for both the carboxy terminal end of the a-nelical segment of collagen and for the beginning of the C-propeptide 1n both genes. Therefore, this organization of exons must have been established before these two collagen genes arose by duplication of a common ancestor. In several subseg-raents the deduced amino acid sequence for the C-propeptide of type III collagen shows a strong homology with the corresponding amino acid sequence in al and a2 type I. For one of these homologous amino add sequences, however, the nucleotide sequence 1s much better conserved than for the others. It 1s possible that a mechanism of gene conversion has maintained the homogeneity of this nucleotide sequence among the interstitial collagen genes. Alternatively, the conserved nucleotide sequence may represent a regulatory signal which could function either 1n the DNA or In the RHA.
*Present address: Ma–PLanck–Institut for Biocheime, 8033 Martinsried, Munchen, FRG