title: mei-W68 in Drosophila melanogaster encodes a Spo11 homolog: evidence that the mechanism for initiating meiotic recombination is conserved.
abstract: Meiotic recombination requires the action of several gene products in both Saccharomyces cerevisiae and Drosophila melanogaster. Genetic studies in D. melanogaster have shown that the mei-W68 gene is required for all meiotic gene conversion and crossing-over. We cloned mei-W68 using a new genetic mapping method in which P elements are used to promote crossing-over at their insertion sites. This resulted in the high-resolution mapping of mei-W68 to a <18-kb region that contains a homolog of the S. cerevisiae spo11 gene. Molecular analysis of several mutants confirmed that mei-W68 encodes an spo11 homolog. Spo11 and MEI-W68 are members of a family of proteins similar to a novel type II topoisomerase. On the basis of this and other lines of evidence, Spo11 has been proposed to be the enzymatic activity that creates the double-strand breaks needed to initiate meiotic recombination. This raises the possibility that recombination in Drosophila is also initiated by double-strand breaks. Although these homologous genes are required absolutely for recombination in both species, their roles differ in other respects. In contrast to spo11, mei-W68 is not required for synaptonemal complex formation and does have a mitotic role.
authors.affiliation: Waksman Institute, Rutgers University, Piscataway, New Jersey 08854-8020, USA. mckim@rci.rutgers.edu,
authors.forename: K S
authors.initials: KS
authors.lastname: McKim
authors.forename: A
authors.initials: A
authors.lastname: Hayashi-Hagihara
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002874:Chromosome Mapping; D003001:Cloning, Molecular; D003433:Crosses, Genetic; D003434:Crossing Over, Genetic; D017931:DNA Primers / Q000235:genetics; D004264:DNA Topoisomerases, Type I / Q000235:genetics; D018076:DNA, Complementary / Q000235:genetics; D004331:Drosophila melanogaster / Q000235:genetics*; D005260:Female; D017344:Genes, Insect; D019476:Insect Proteins / Q000235:genetics; D008297:Male; D008540:Meiosis / Q000235:genetics*; D008969:Molecular Sequence Data; D009154:Mutation; D016133:Polymerase Chain Reaction; D011995:Recombination, Genetic; D012441:Saccharomyces cerevisiae / Q000235:genetics; D013045:Species Specificity; D013573:Synaptonemal Complex / Q000235:genetics
chemical_list: D017931:DNA Primers; D018076:DNA, Complementary; D019476:Insect Proteins; D004264:DNA Topoisomerases, Type I