Worm Breeder's Gazette 16(1): 41 (October 1, 1999)

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.

Functional analysis of the T17A3 .1 encoded gene which is structurally related to vertebrate VEGFRs .

Cornel Popovici1, Daniel Isnardon2, Marie-José Santoni1, Daniel Birnbaum1, Régine Roubin1,3

1 INSERM U119, 27 Bd Leï Roure, 13009, Marseille, France
2 Institut Paoli-Calmettes, 232 Bd Saite Marguerite, 13009, Marseille, France
3 roubin@marseille.inserm.fr

A phylogenic analysis has unvealed a family of four Tyrosine Kinase Receptors structurally related to Vascular Endothelial Growth Factor Receptors (VEGFRs) in the genome of C. elegans (Popovici et al, Genome Res., 1999, in press). These genes are carried by the F59F3 and T17A3 cosmids. One EST for the geneF59F3.1 already existed in the Yugi Kohara's collection, and we were able to amplify two others (F59F3.5 and T17A3.1) by RT-PCR. RNAi done on 2 of them indicated that these genes were not redundant.

We focused on the T17A3.1 gene and studied its pattern of expression using a GFP fusion reporter gene. The major sites of expression are in a few neuronal structures localized in the head and the tail, some corresponding to amphid and phasmid neurons and/or sheaths, in the first and last intestinal cells and the intestinal muscle.

Double strand RNA was injected in wild type animals containing the T17A3.1::GFP fusion gene and pRF4 encoding rol-6 as an extrachromosomal array. RNAi induced various phenotypes, the milder being an impairment of amphid and phasmid neurons dye filling associated with a deformation of the sheath cells. In some experiments, the RNAi induced phenotype was transmissible for several generations. Indeed we established several strains exhibiting a more or less similar phenotype. The phenotype is more severe than for the transitory RNAi, since the RNAi strains exhibit various abnormal cell migrations, for some head neurons and likely DTC since very often premature arrest in gonade development, duplication of gonade arms or gonade misshaping occur. Fertility is reduced, with animals laying numerous dead embryos. Animals are slightly unc and have either a protruding vulva or an egl phenotype. Some animals have also a clr phenotype due to the presence of liquid in the coelomic cavity.

We are hoping to get the null allele that we have requested from the KO consortium to confirm these phenotypes. We are also looking for the ligand(s) for this tyrosine kinase receptor using bioinformatic, biochemical and genetic tools.