Rays are the peripheral sensory structures developed in the tail of the male nematode, Caenorhabditis elegans. Each of these rays has its own specific morphological and functional identities. Their differentiation is governed by a number of genes which act upon each other to guide the ray morphogenesis. Mutations in these genes result in a transformation of ray identity. One of these genes, mab-21, has pleiotropic phenotypes when it is mutated. Transformation of ray 6 into ray 4 and subsequent fusion of them is observed. It has been shown that mab-21 is interacting with a number of evolutionarily conserved molecules. Here I show that analysis of the dynamic expression pattern of mab-21, and its regulatory promoter elements reveals more information on the regulatory pathway. Furthermore,...[ Read more ]

Rays are the peripheral sensory structures developed in the tail of the male nematode, Caenorhabditis elegans. Each of these rays has its own specific morphological and functional identities. Their differentiation is governed by a number of genes which act upon each other to guide the ray morphogenesis. Mutations in these genes result in a transformation of ray identity. One of these genes, mab-21, has pleiotropic phenotypes when it is mutated. Transformation of ray 6 into ray 4 and subsequent fusion of them is observed. It has been shown that mab-21 is interacting with a number of evolutionarily conserved molecules. Here I show that analysis of the dynamic expression pattern of mab-21, and its regulatory promoter elements reveals more information on the regulatory pathway. Furthermore, this study will also facilitate the isolation of components interacting with the gene and the delineation of part of this neuronal identity determination mechanism.

This study focuses on the analysis of promoter activity of mab-21 by producing a series of unidirectional deletion mutations of the promoter sequence. Assay by reporter constructs revealed that expression of mab-21 in the embryo is dependent on cis-elements confined to -341 bp to -316 bp from the transcription start site. Elements encompassed by -374 to -316 bp were also shown to be essential for mab-21 expression in the larval stage. The potential implication of these elements will be discussed. These findings are important for further definition of precise regulatory elements on the promoter, and identification of trans-acting factors that govern mab-21 expression.