Localized Bicaudal-C RNA encodes a protein containing a KH domain, the RNA binding motif of FMR1.
The Bicaudal-C (Bic-C) gene of Drosophila melanogaster is required for correct targeting of the migrating anterior follicle cells and for specifying anterior position. Females lacking any wild type copies of Bic-C produce only eggshells open at the anterior end, because of the failure of the columnar follicle cells to migrate in the correct position at the nurse cell--oocyte boundary. Embryos which develop from eggs produced in females with only one wild type copy of Bic-C show defects in anterior patterning and an abnormal persistence of oskar RNA in anterior regions. We cloned Bic-C and found that, in ovaries, Bic-C RNA is expressed only in germline cells. Bic-C RNA is localized to the oocyte in early oogenesis, and later concentrates at its anterior cortex. The Bic-C protein includes five KH domains similar to those found in the human fragile-X protein FMR1. Alteration of a highly conserved KH domain codon by mutation abrogates in vivo Bic-C function. These results suggest roles for the Bic-C protein in localizing RNAs and in intercellular signaling.
Mahone
M
M
Department of Biology, McGill University, Montréal, Québec, Canada.
Saffman
E E
EE
Lasko
P F
PF
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D003001:Cloning, Molecular; D004247:DNA / Q000235:genetics; D029721:Drosophila Proteins; D004331:Drosophila melanogaster / Q000196:embryology / Q000235:genetics / Q000378:metabolism; D005260:Female; D051860:Fragile X Messenger Ribonucleoprotein 1; D017344:Genes, Insect; D006801:Humans; D007301:Insect Hormones / Q000235:genetics*; D008297:Male; D008969:Molecular Sequence Data; D009419:Nerve Tissue Proteins / Q000378:metabolism*; D009865:Oocytes / Q000378:metabolism; D010641:Phenotype; D012313:RNA / Q000235:genetics* / Q000378:metabolism; D012326:RNA Splicing; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D016601:RNA-Binding Proteins / Q000235:genetics* / Q000378:metabolism*; D020794:Receptor Protein-Tyrosine Kinases / Q000235:genetics; D015398:Signal Transduction
D004247:DNA; D029721:Drosophila Proteins; D051860:Fragile X Messenger Ribonucleoprotein 1; D007301:Insect Hormones; D009419:Nerve Tissue Proteins; D012313:RNA; D012333:RNA, Messenger; D016601:RNA-Binding Proteins; D020794:Receptor Protein-Tyrosine Kinases; C061998:BicD protein, Drosophila; C497683:FMR1 protein, human