AbstractBackground: Many genes are meiosis and/or sporulation‐specifically transcribed during this process. Isolation and analysis of these genes might help us to understand how meiosis and sporulation are regulated. For this purpose, we have isolated a large number of cDNA clones from Schizosaccharomyces pombe whose expression is up‐regulated during meiosis.Results: We have isolated meu10+ gene, which encodes 416 amino acids and bears homology to SPS2 of Saccharomyces cerevisiae. A strain whose meu10+ gene has been deleted forms no viable spores. Thin‐section electron micrographs showed that the meu10Δ strain has abnormally formed spore walls, and then they disrupt, allowing cytoplasmic material to escape. The Meu10‐GFP fusion protein is localized to the spore periphery, thereafter returned to the cytoplasm after sporulation. Meu10‐GFP localization to the spore wall was almost normal in the bgs2Δ or chs1Δ mutants that lack 1,3‐β‐glucan or chitin, respectively. In contrast, 1,3‐β‐glucan is abnormally localized in meu10Δ cells. Meu10 has an N‐terminal domain with homology to the mammalian insulin receptor and a C‐terminal domain with a transmembrane motif. Mutants whose N‐terminal or C‐terminal domain was truncated were severely defective for sporulation.Conclusions: Meu10 is a spore wall component and plays a pivotal role in the formation of the mature spore wall structure.