Characterization of a novel gene expressed in neuromuscular tissues and centrosomes in Caenorhabditis elegans

The nematode Caenorhabditis elegans has many advantages for studying gene function at the organism level. In particular, completion of the genome sequencing has made it feasible to study gene structure and function of both known and novel proteins. As a result of a database search for muscle-specific genes, a gene F43D9.1 was found which showed muscle-specific expression as revealed by the in situ hybridization pattern from the Expressed Sequence Tag (EST) database. A homology search of F43D9.1 protein sequences showed no significant homology with other known proteins, except that it showed very weak sequence similarity with the band 4.1 protein superfamily. Northern blot analysis reveals a single transcript 3.7 kb in size which is consistent with the predicted gene structure. The expression pattern of F43D9.1 was investigated using the gfp reporter gene, and it has shown to be expressed in neuronal cells including sensory neurons and interneurons in the head region. To further characterize F43D9.1, whole-mount immunostaining was performed with anti-F43D9.1 antibody, which showed specific signals in head neurons, body-wall muscle cells, some other unidentified neuronal cells, and centrosomes of the dividing cells during embryogenesis. Taken together with its predicted membrane topology, we speculate that the F43D9.1 gene, which encodes a novel transmembrane protein and contains a band 4.1-like domain, may function in neuromuscular cells, and may play an important role during cell division in C. elegans.