Characterization of the essential receptor tyrosine kinase rol-3 in C. elegans

rol-3 is a member of the Roller phenotypic class of mutations that affect gross morphology in C. elegans. All identified Roller mutations affect cuticle specific collagens with the exception of rol-3, which is unique in that it encodes a receptor tyrosine kinase (RTK) similar to the human oncogenic orphan receptor, c-ROS. Ten recessive lethal alleles have previously been isolated by our laboratory demonstrating that ROL-3 function is essential for the development of this animal. To better the understanding of the developmental role of rol-3, I have investigated this gene at both the genetic and molecular level. Analysis of the allelic series of rol-3 mutations reveals that the non-lethal Roller alleles specifically disrupt the extracellular domain of the protein while severe alleles arise from protein truncations or disruption of the kinase domain. rol-3 expression is restricted to the hypodermis, and is required for development of the seam cell syncytium, a specialized set of cells required for synthesis of the cuticle, thus linking rol-3 to the development of tissues that generate the cuticle. I have used whole genome oligo array Comparative Genomic Hybridization to link chromosomal deficiencies and duplications to the genomic sequence, generating a physical mapping resource for the C. elegans research community and have used this resource to confirm the physical region of the suppressor of Roller lethality, srl-2. Additionally, to gain further insight into the function of rol-3, I have generated and identified two new suppressors of rol-3 using a suppressor screen and oligoarray Comparative Genomic Hybridization mapping. I show that the new suppressors of rol-3, the Bicaudal-C homologue bcc-1, and T06E8.1, a secreted mucin, are able to suppress the lethality but not rolling phenotype of the temperature sensitive conditional allele rol-3(s1040).