title: The Ketel gene encodes a Drosophila homologue of importin-beta.
abstract: The Drosophila melanogaster Ketel gene was identified via the Ketel(D) dominant female sterile mutations and their ketel(r) revertant alleles that are recessive zygotic lethals. The maternally acting Ketel(D) mutations inhibit cleavage nuclei formation. We cloned the Ketel gene on the basis of a common breakpoint in 38E1. 2-3 in four ketel(r) alleles. The Ketel(+) transgenes rescue ketel(r)-associated zygotic lethality and slightly reduce Ketel(D)-associated dominant female sterility. Ketel is a single copy gene. It is transcribed to a single 3.6-kb mRNA, predicted to encode the 97-kD Ketel protein. The 884-amino-acid sequence of Ketel is 60% identical and 78% similar to that of human importin-beta, the nuclear import receptor for proteins with a classical NLS. Indeed, Ketel supports import of appropriately designed substrates into nuclei of digitonin-permeabilized HeLa cells. As shown by a polyclonal anti-Ketel antibody, nurse cells synthesize and transfer Ketel protein into the oocyte cytoplasm from stage 11 of oogenesis. In cleavage embryos the Ketel protein is cytoplasmic. The Ketel gene appears to be ubiquitously expressed in embryonic cells. Western blot analysis revealed that the Ketel gene is not expressed in several larval cell types of late third instar larvae.
authors: Faculty of General Medicine, Department of Biology, University of Szeged, H-6720 Szeged, Hungary.
authors: M
authors: M
authors: Lippai
authors: L
authors: L
authors: Tirián
authors: I
authors: I
authors: Boros
authors: J
authors: J
authors: Mihály
authors: M
authors: M
authors: Erdélyi
authors: I
authors: I
authors: Belecz
authors: E
authors: E
authors: Máthé
authors: J
authors: J
authors: Pósfai
authors: A
authors: A
authors: Nagy
authors: A
authors: A
authors: Udvardy
authors: E
authors: E
authors: Paraskeva
authors: D
authors: D
authors: Görlich
authors: J
authors: J
authors: Szabad
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D030801:Animals, Genetically Modified; D002467:Cell Nucleus / Q000378:metabolism; D003001:Cloning, Molecular; D003593:Cytoplasm / Q000378:metabolism; D018076:DNA, Complementary / Q000235:genetics; D004331:Drosophila melanogaster / Q000196:embryology / Q000235:genetics*; D004625:Embryo, Nonmammalian / Q000166:cytology / Q000378:metabolism; D005260:Female; D005799:Genes, Dominant; D017344:Genes, Insect; D005804:Genes, Lethal; D006367:HeLa Cells / Q000378:metabolism; D006801:Humans; D007247:Infertility, Female / Q000235:genetics; D019476:Insect Proteins / Q000235:genetics*; D028884:Karyopherins; D008969:Molecular Sequence Data; D009687:Nuclear Proteins / Q000235:genetics* / Q000502:physiology; D009928:Organ Specificity; D021381:Protein Transport / Q000235:genetics*; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D013045:Species Specificity; D019076:Transgenes; D015053:Zygote
chemical_list: D018076:DNA, Complementary; D019476:Insect Proteins; D028884:Karyopherins; D009687:Nuclear Proteins