High impact information on collagen

• The major differences between the genes is that, preceding the initiator ATG, col-12 has a cis-spliced intron, while col-13 is transspliced [1].
• We have determined the complete nucleotide sequences of two collagen genes, col-12 and col-13, that are separated by only 1800 bases and are transcribed in the same direction [1].
• Homology in the flanking sequence has allowed us to unambiguously identify this gene as the col-12 homologue, as opposed to some other closely related member of this large multigene family [2].

Biological context of collagen

• The amino acid sequences are identical except for two conservative amino acid changes within the putative secretory signal sequences, so the mature forms of the col-12 and col-13 collagens would be identical [1].
• In contrast to the coding regions and the introns, the 5' and 3' flanking regions show little sequence similarity, col-12 and col-13 are expressed at similar levels at the same developmental stages, and appear to utilize conserved TATA boxes and transcription start sites [1].
• These results suggest that col-12 and col-13 are derived from a gene duplication and that sequence homology in the coding regions, but not in the flanking regions, has been maintained by gene conversion [1].
• We conclude that the gene duplication event that resulted in the creation of col-12 and col-13 in C. elegans is most likely the same duplication that generated colost-1 and colost-2 in O. circumcincta, and thus this particular gene duplication precedes the divergence of the two species [3].

References