title: Drosophila mojoless, a retroposed GSK-3, has functionally diverged to acquire an essential role in male fertility.
abstract: Retroposition is increasingly recognized as an important mechanism for the acquisition of new genes. We show that a glycogen synthase kinase-3 gene, shaggy (sgg), retroposed at least 50 MYA in the Drosophila genus to generate a new gene, mojoless (mjl). We have extensively analyzed the function of mjl and examined its functional divergence from the parental gene sgg in Drosophila melanogaster. Unlike Sgg, which is expressed in many tissues of both sexes, Mjl is expressed specifically in the male germ line, where it is required for male germ line survival. Our analysis indicates that mjl has acquired a specific function in the maintenance of male germ line viability. However, it has not completely lost its ancestral biochemical function and can partially compensate for loss of the parental gene sgg when ectopically expressed in somatic cells. We postulate that mjl has undergone functional diversification and is now under stabilizing selection in the Drosophila genus.
authors.affiliation: Laboratory of Cellular and Developmental Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland, USA. rasika@niddk.nih.gov
authors.forename: Rasika
authors.initials: R
authors.lastname: Kalamegham
authors.forename: David
authors.initials: D
authors.lastname: Sturgill
authors.forename: Esther
authors.initials: E
authors.lastname: Siegfried
authors.forename: Brian
authors.initials: B
authors.lastname: Oliver
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D016000:Cluster Analysis; D017931:DNA Primers; D004330:Drosophila / Q000235:genetics*; D029721:Drosophila Proteins / Q000235:genetics* / Q000378:metabolism; D005298:Fertility / Q000235:genetics; D005854:Germ Cells / Q000378:metabolism; D038362:Glycogen Synthase Kinase 3 / Q000235:genetics* / Q000378:metabolism; D015151:Immunoblotting; D016013:Likelihood Functions; D008297:Male; D018613:Microscopy, Confocal; D008957:Models, Genetic; D008969:Molecular Sequence Data; D034622:RNA Interference; D018626:Retroelements / Q000235:genetics*; D012641:Selection, Genetic; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA; D013737:Testis / Q000166:cytology / Q000378:metabolism
chemical_list: D017931:DNA Primers; D029721:Drosophila Proteins; D018626:Retroelements; C080335:Sgg protein, Drosophila; D038362:Glycogen Synthase Kinase 3; C522123:gskt protein, Drosophila