|Budget Amount *help
¥3,100,000 (Direct Cost : ¥3,100,000)
Fiscal Year 1999 : ¥1,400,000 (Direct Cost : ¥1,400,000)
Fiscal Year 1998 : ¥1,700,000 (Direct Cost : ¥1,700,000)
We identified a novel gene of Drosophila melanogaster, ms-I, encoding a predicted transmembrane signaling molecule with exclusive expression in the testis. This gene encodes a new member of IDGF, a soluble growth factor for embryonic cells of the flesh fly, Sarcophaga peregrina. The gene product (MSI) has a single transmembrane region, which separates this protein into a long C-terminal extracellular domain showing significant homology with IDGF and a short N-terminal intracellular domain, suggesting that it is a membrane-bound extracellular signaling molecule. Gene expression analysis revealed that ms-I is expressed exclusively in , the testis, where its transcript is present in mature primary spermatocytes. Analysis using four meiotic arrest mutants, aly, can, mia and sa suggested that MSI is involved in spermiogenesis, the final differentiation step of spermatogenesis, rather than meiosis.