Worm Breeder's Gazette 8(1): 39
These abstracts should not be cited in bibliographies. Material contained herein should be treated as personal communication and should be cited as such only with the consent of the author.
We have been studying the collagen gene family of C. elegans for insights into the regulatory and assembly processes that create the distinct cuticles formed at the molts. We have found that the collagen gene family contains 50-150 members, the majority of which, we believe, encode cuticle collagens. Genetic mapping using Bristol/Bergerac polymorphisms has shown that members of the gene family are scattered throughout the genome, with the exception of one 'cluster' of 4 genes localized within a 2-3 map unit region on chromosome IV. Evidence from phage and cosmid clones also indicates that most genes are widely separated. The times of transcription throughout the life cycle have been determined for about 20 genes by Northern blot analysis and by probing cloned genes with labeled, stage- specific cDNA's. Several different patterns of transcription are seen, but the genes can be roughly grouped into four categories based on the stages during which they are transcribed. Location in the genome does not appear to be important for the control of transcription since genes with the same pattern of expression are found on different chromosomes, while genes within the 'cluster' on chromosome IV have different expression patterns. We are therefore pursuing the idea that the different patterns of transcription are controlled by specific regulatory sequences that lie near or within each gene. We reported the DNA sequences of two collagen genes, col-1 and col-2, earlier (Kramer et al. (1982) Cell 30, 599). We have found that col- 1 and col-2 are transcribed with different temporal patterns and we have recently analyzed their transcripts using S1 nuclease digestion mapping. We have found that both transcripts begin approximately 30 nucleotides before the initiator methionine codon and end approximately 12 nucleotides beyond the AATAAA poly-A addition signals. Major homologies in the 5 - upstream region are: an 8 nucleotide stretch at the start of each transcript that may be a ribosome recognition sequence, 8 nucleotides that include the 'TATAA' box, and a repeated sequence (TTTCCAGT) ,found between nucleotides 200 to 300 in both collagen genes and also in an MSP gene cloned by M. Klass. We are intrigued to know whether this repeated sequence has any special transcriptional functions. We currently are completing the sequences of 5 more collagen genes so that sequence comparisons can be made among with genes having different patterns of expression.