Jagan Srinivasan et al. (2002) Worm Breeder's Gazette "Towards a Pristionchus genome map II - Microevolutionary analysis of the nematode genus Pristionchus"

Ralf J Sommer, Min Zheng, Isabel Kipping, Arturo Gutierrez, Andre Pires da Silva, Hanh Witte, Jagan Srinivasan

[Worm Breeder's Gazette, 2002]

We describe the molecular characterization of laboratory strains of the nematode genus Pristionchus , which lays a foundation for microevolutionary analyses of vulva development. We isolated 13 laboratory strains of the Pristionchus genus that are derived from natural isolates from around the world. Mating experiments and ITS sequence analysis indicated that these 13 strains represent four different species; the gonochoristic species P. lheritieri and three hermaphroditic species, P. pacificus , P. maupasi and an as yet undescribed species Pristionchus sp., respectively. P. pacificus is represented by five different strains isolated from California, Washington, Hawaii, Ontario and Poland. Our working 'wild type' strain is the California strain. Since polymorphisms are becoming an important tool in modern day genomic analysis, which facilitate cloning of mutations, we decided to search for polymorphisms in the various Pristionchus pacificus strains. We performed amplified restriction fragment length polymorphism (AFLP) analyses of the different P. pacificus strains and found that the American strains are highly polymorphic (Srinivasan et al., 2001). We observed the largest genetic variation between the strain from California on the one hand and Washington and Hawaii on the other hand. In contrast, the developmentally distinct strain from Poland is identical to the Californian strain. Hence, we chose the Washington strain as our polymorphic strain for future experiments. These results provide us a framework for further studies on microevolution in developmental processes. Reference: Srinivasan, J., Pires-daSilva, A.; Gutierrez, A.; Jungblut, B.; Zheng, M.; Witte, H.; Schlak., I. & Ralf J. Sommer, Evolution & Development (2001) 3 : 229-240.

Wang WF et al. (1994) Worm Breeder's Gazette "Cloning and Characterization of a C. elegans Homologue of 14-3-3, a Highly Conserved Gene Thought To Be Involved in Intracellular Signalling"

Shakes DC, Wang WF

[Worm Breeder's Gazette, 1994]

In the course of looking for the par-5 gene, we discovered (with help from Sherry Dickens of the Kemphues' lab) a 3.8 kb EcoR1 fragment of the cosmid C38H7 which appeared to encode transcripts which were considerably more abundant in wildtype hermaphrodites than in glp-4 (germline-less) hermaphrodites. Finding this to be a promising characteristic, we used this genomic fragment to isolate seven cDNAs from both the early embryonic Schauer/Wood library and the Okkema/Fire mixed stage library. One of these clones has now been sequenced. The sequence results demonstrated that this cDNA clone contains an ORF with 248 amino acids, and deduced the amino acid sequence shares 77.6%, 77.6%, 77.1%, 76.3%, 76.9%, 61.4% and 62.9% identity with bovine, Drosophila, human, sheep, Xenopus, plant(Oenothera) and Saccharomyces cerevisiae forms of 14-3-3 protein respectively. Like these other genes, the C. elegans version includes a putative pseudosubstrate domain for protein kinase C (GARR), an annexin-like domain which is thought to bind to protein kinase C, and a highly acidic C-terminus. 14-3-3 proteins are highly conserved, soluble acidic proteins which appear to be involved primarily in intracellular signalling (Aitken et al., 1992, TIBS 17: 498-501). However, their function remains controversial since different groups have implicated them in the following diverse functions: 1) an activator of tyrosine and tryptophan hydroxylases, 2) an activator, inhibitor, or translocator of protein kinase C, 3) an activator of ADP-ribosyltransferase, and 4) a component of G-box binding transcription factors in plants. When we used our cDNA clone Ce14 -3-3to probe a blot containing the total cellular RNA from both N2 and glp-4 adult hermaphrodites, three bands (transcripts) with the sizes of 1.5, 1.35 and 0.9 kb respectively were seen in both samples. However, all three transcripts were more abundant in wild type worms. This result suggested that A). Ce14 -3-3may have isoforms or closely related members as has been observed for other species and B). Ce14 -3-3'stranscription is germ-line enhanced. When Ce143 -3was used to probe genomic Southern blots it hybridized strictly to the predicted 3.8 kb EcoR1 band under hybridization conditions similar to the Northern blot. This result suggests that the 3 different Ce14 -3-3transcripts are products of differential RNA processing rather than different genes. Work is currently in progress to determine if the transcripts differ in their protein coding sequences.