cell biochemistry and function Cell Biochem Funct 2001; 19: 79±88. DOI: 10.1002/cbf.880 Characterization of a novel gene expressed in neuromuscular tissues and centrosomes in Caenorhabditis elegans Soonjae Kwon, Woo Keun Song, Chul-Seung Park and Joohong Ahnn * Department of Life Science, Kwangju Institute of Science and Technology, Kwangju, 500-712, Korea 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-speci®c genes, a gene F43D9.1 was found which showed muscle-spe- ci®c expression as revealed by the in situ hybridization pattern from the Expressed Sequence Tag EST) database. A homol- ogy search of F43D9.1 protein sequences showed no signi®cant 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 speci®c signals in head neurons, body-wall muscle cells, some other unidenti®ed 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 neu- romuscular cells, and may play an important role during cell division in C. elegans. Copyright # 2001 John Wiley & Sons, Ltd. key words Ð Caenorhabditis elegans; green ¯uorescent protein; body-wall muscle; sensory neuron; centrosomes; transmembrane protein; band 4.1 abbreviations ÐEST, Expressed Sequence Tag; CGC, C. elegans Genetics Center; T3, bacteriophage T3; T7, bacteriophage T7; Tri reagent, total RNA isolation reagent; PCR, polymerase chain reaction; GFP, green ¯uorescent protein; GST, glutathione S-tranferase; IPTG, isopropyl--D-thiogalactoside; SDS- PAGE, sodium dodecyl sulfate-polyacrylamide gel electrophoresis; HRP, horse-radish peroxidase; HEPES, 4-2-hydroxyethyl)-1-piperazineethanesulfonic acid; TBS-T, Tris buffered solution with Tween 20; LG, linkage group; TM, transmembrane INTRODUCTION The nematode Caenorhabditis elegans is an excellent model system in which to study gene function at the organism level. 1±3 Some of the advantages of using C. elegans are its transparency, simple body structure, short life cycle 3 days at 20  C), and suitability for genetic analysis. Differential interference contrast microscopy 4 has made it possible to study its com- plete cell lineage during embryogenesis. 5 Transgenic animals can also be obtained by microinjection of DNA into C. elegans, and this technique has been widely used to characterize gene expression. 6,7 The complete sequence of the C. elegans genome has been reported recently 8 and over 19,000 genes have been predicted from the nearly complete sequenced genes. The physical map was revealed by the sequence information and has made it possible to correlate this map with the well-studied genetic map. 9,10 Besides, rescue of many mutants which had been identi®ed genetically made cloning of genes and Copyright # 2001 John Wiley & Sons, Ltd. Received 4 February 2000 Accepted 28 February 2000 *Correspondence to: Joohong Ahnn, Department of Life Science, Kwangju Institute of Science and Technology, 1 Oryong- dong, Puk-Gu, Kwangju 500-712, Korea. Tel: 82 62 970 2488. Fax: 82 62 970 2484. E-mail: joohong@eunhasu.kjist.ac.kr