Identification and characterization of an SPO11 homolog in the mouse

The SPO11/TOPVIA family includes proteins from archaebacteria and eukaryote s. The protein mem ber from the archaebacterium Sulfulobus shibatae is the catalytic subunit of TopoVI DNA topoisomerase. In Saccharomyces cerevisiae, Schizosaccharomyces pombe, Caenorhabditis elegans and Drosophila melanogas ter, SPO11 is required for meiotic recombination, suggesting a conserved me chanism for the initiation step of this process. Indeed, S. cerevisiae SPO1 1 has been shown to be directly involved in the formation of meiotic DNA do uble-strand breaks that initiate meiotic recombination. Here, we report the identification of a Mus musculus Spo11 cDNA, which encodes a protein close ly related to all members of the SPO11/TOPVIA family. cDNAs resulting from alternative splicing were detected, suggesting that there are potential var iants of the mouse SPO11 protein. By RNA-blotting analysis, expression of t he mouse Spo11 gene was detected only in the testis, in agreement with its predicted function in the initiation of meiotic recombination. We mapped th e mouse Spo11 gene to chromosome 2, band H2-H4.