title: Cytoplasmic localization and evolutionary conservation of MEI-218, a protein required for meiotic crossing-over in Drosophila.
abstract: During Drosophila oogenesis, the oocyte is formed within a 16-cell cyst immediately after four incomplete cell divisions. One of the primary events in oocyte development is meiotic recombination. Here, we report the intracellular localization of the MEI-218 protein that is specifically required for meiotic crossing-over. To understand the role of mei-218 in meiosis and to study the regulation of genes required for meiotic recombination, we characterized the expression pattern of its RNA and protein. Furthermore, we cloned and sequenced mei-218 from two other Drosophila species. The mei-218 RNA and protein have a similar expression pattern, appearing first in early meiotic prophase and then rapidly disappearing as prophase is completed. This pattern corresponds to a specific appearance of the mei-218 gene product in the region of the ovary where meiotic prophase occurs. Although mei-218 is required for 95% of all crossovers, the protein is found exclusively in the cytoplasm. Based on these results, we suggest that mei-218 does not have a direct role in recombination but rather regulates other factors required for the production of crossovers. We propose that mei-218 is a molecular link between oocyte differentiation and meiosis.
authors.affiliation: Waksman Institute, Rutgers University, Piscataway, New Jersey 08854-8020.
authors.forename: Elizabeth A
authors.initials: EA
authors.lastname: Manheim
authors.forename: Janet K
authors.initials: JK
authors.lastname: Jang
authors.forename: Danielle
authors.initials: D
authors.lastname: Dominic
authors.forename: Kim S
authors.initials: KS
authors.lastname: McKim
mesh_terms: D020413:3' Untranslated Regions / Q000378:metabolism; D000595:Amino Acid Sequence; D000818:Animals; D018797:Cell Cycle Proteins / Q000737:chemistry / Q000235:genetics* / Q000276:immunology / Q000378:metabolism*; D017124:Conserved Sequence; D003434:Crossing Over, Genetic; D003593:Cytoplasm / Q000737:chemistry; D004330:Drosophila / Q000196:embryology / Q000235:genetics* / Q000378:metabolism; D029721:Drosophila Proteins / Q000737:chemistry / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D019143:Evolution, Molecular; D005260:Female; D018507:Gene Expression Regulation, Developmental; D017403:In Situ Hybridization; D008540:Meiosis; D018613:Microscopy, Confocal; D009154:Mutation; D009866:Oogenesis; D010053:Ovary / Q000166:cytology; D010641:Phenotype; D017386:Sequence Homology, Amino Acid; D014158:Transcription, Genetic
chemical_list: D020413:3' Untranslated Regions; D018797:Cell Cycle Proteins; D029721:Drosophila Proteins; C103176:mei-218 protein, Drosophila