Worm Breeder's Gazette 12(4): 41 (October 1, 1992)

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.

Characterization of the msp-113 Gene Cluster in Strains of Caenorhabditis elegans

Robert A. Setterquist, G. Kenneth Smith, David Ammons, George E. Fox

Dept. Biochemical Sciences, University of Houston, Houston, Texas 77204-5934

We are using the major sperm protein (MSP) gene family found in nematodes as a model system to gain insight to genomic evolution. It would be of special interest to examine msp genes from strains or species which are sufficiently similar that a one to one correspondence of genes with those of the Bristol strain could be established in order to gain insight to how frequently new genes are created. To attempt a study of this type we selected the msp-113 gene cluster of C. elegans strain Bristol, which is known to have at least six msp genes of which four have been sequenced to date. This cluster is of special interest because its members are most alike in terms of gene sequence and therefore may be the most recently evolved cluster in the Bristol strain.

Two C. elegans strains, the French strain BO and the Australian strain AB1 were examined. Earlier work (Thomas & Wilson Genetics 128: 269-279,1991) with the mitochondrial cytochrome oxidase gene showed that whereas strain BO 1 was virtually identical to the Bristol strain, the AB1 strain did exhibit some variation. In order to rapidly characterize genes in AB1 a msp-113 cluster specific PCR primer was constructed for a sequence region approximately 100 nucleotides upstream from the msp start codon and a conserved region surrounding the stop codon. Resulting amplification products were cloned into TA vector (InVitrogen Inc.) and sequenced using msp specific primers. A total of 11 clones yielded 9 unique msp gene sequences, eight of which belonged to the msp-113 cluster based on sequence comparison. Two of these genes were effectively identical to known Bristol sequences. Another two were unusual in that they contained a three amino acid insertion shortly after the start codon which is not found in any known msp gene (regardless of cluster) in Bristol. Two msp genes belonging to the msp-113 cluster were also sequenced from lambda clones of the BO strain. One of these was unique while the other was identical to one of the AB1 msp genes with the amino acid insertion.

Are there genes in the AB1 analog of the msp-113 gene cluster that are not in the Bristol strain? We really can't tell at this stage. In order to accommodate the results there would have to be at least 10 genes in the msp-113 cluster of the Bristol strain. We are currently using the obvious PCR amplification approach to search for the missing genes in Bristol and plan a more formal examination of cosmids from the msp-113 region as well in order to localize any missing genes that are found.

Literature Cited:

Thomas & Wilson Genetics 128: 269-279,1991.