Expression of the Caenorhabditis elegans collagen genes col-1 and col-2 is developmentally regulated

The total collagen gene expression as well as the specific expression of two sequenced Caenorhabditis elegans collagen genes, col-1 and col-2, has been investigated. Northern blots of RNA isolated from animals at different developmental stages were probed under conditions that allow cross-hybridization of all collagen sequences. The majority of hybridization is to transcripts of 1.1-1.4 kilobases (kb) in length, with weak hybridization to some larger transcripts. Different size patterns, within the 1.1-1.4-kb ranges, are seen in RNAs from different developmental stages. Gene-specific probes were produced from the C. elegans collagen genes col-1 and col-2, and each was shown to hybridize to a single size transcript in the 1.1-1.4-kb region. The col-1 transcript was found in all the developmental stages examined, but its abundance varied between stages. The col-2 transcript was detected only in a single developmental stage, during formation of the dauer larvae. The 5' and the 3' ends of the col-1 and col-2 transcripts were determined by S1 nuclease digestion experiments. Both genes have the common "TATA" and "CAAT" box sequences preceding the 5' end of their transcripts and there is strong sequence homology in their 5' untranslated regions. Multiple copies of an eight-nucleotide repeat sequence were found upstream from both col-1 and col-2.