maelstrom is required for an early step in the establishment of Drosophila oocyte polarity: posterior localization of grk mRNA.
We describe a mutant, maelstrom, that disrupts a previously unobserved step in mRNA localization within the early oocyte, distinct from nurse-cell-to-oocyte RNA transport. Mutations in maelstrom disturb the localization of mRNAs for Gurken (a ligand for the Drosophila Egf receptor), Oskar and Bicoid at the posterior of the developing (stage 3-6) oocyte. maelstrom mutants display phenotypes detected in gurken loss-of-function mutants: posterior follicle cells with anterior cell fates, bicoid mRNA localization at both poles of the stage 8 oocyte and ventralization of the eggshell. These data are consistent with the suggestion that early posterior localization of gurken mRNA is essential for activation of the Egf receptor pathway in posterior follicle cells. Posterior localization of mRNA in stage 3-6 oocytes could therefore be one of the earliest known steps in the establishment of oocyte polarity. The maelstrom gene encodes a novel protein that has a punctate distribution in the cytoplasm of the nurse cells and the oocyte until the protein disappears in stage 7 of oogenesis.
Clegg
N J
NJ
Department of Biochemistry, University of Washington, Seattle 98195-7350, USA.
Frost
D M
DM
Larkin
M K
MK
Subrahmanyan
L
L
Bryant
Z
Z
Ruohola-Baker
H
H
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D016764:Cell Polarity / Q000235:genetics; D003001:Cloning, Molecular; D004247:DNA / Q000235:genetics; D029721:Drosophila Proteins; D004331:Drosophila melanogaster / Q000235:genetics* / Q000254:growth & development* / Q000378:metabolism; D066246:ErbB Receptors / Q000235:genetics; D005260:Female; D018507:Gene Expression Regulation, Developmental; D017344:Genes, Insect; D019476:Insect Proteins / Q000235:genetics* / Q000378:metabolism; D008870:Microtubules / Q000378:metabolism / Q000648:ultrastructure; D008969:Molecular Sequence Data; D009154:Mutation; D009865:Oocytes / Q000166:cytology / Q000378:metabolism*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D016211:Transforming Growth Factor alpha; D015291:Transforming Growth Factors / Q000235:genetics* / Q000378:metabolism
D029721:Drosophila Proteins; D019476:Insect Proteins; D012333:RNA, Messenger; D016211:Transforming Growth Factor alpha; C083730:grk protein, Drosophila; C109767:mael protein, Drosophila; D015291:Transforming Growth Factors; D004247:DNA; D066246:ErbB Receptors