Translational regulation of oskar mRNA by bruno, an ovarian RNA-binding protein, is essential

Cell. 1995 May 5;81(3):403-12. doi: 10.1016/0092-8674(95)90393-3.


Oskar (osk) protein directs the deployment of nanos (nos), the posterior body-patterning morphogen in Drosophila. To avoid inappropriate activation of nos, osk activity must appear only at the posterior pole of the oocyte, where the osk mRNA becomes localized during oogenesis. Here, we show that translation of osk mRNA is, and must be, repressed prior to its localization; absence of repression allows osk protein to accumulate throughout the oocyte, specifying posterior body patterning throughout the embryo. Translational repression is mediated by an ovarian protein, bruno, that binds specifically to bruno response elements (BREs), present in multiple copies in the osk mRNA 3'UTR. Addition of BREs to a heterologous mRNA renders it sensitive to translational repression in the ovary.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Base Sequence
  • Binding Sites
  • Cell Compartmentation
  • Drosophila Proteins*
  • Drosophila melanogaster / embryology*
  • Drosophila melanogaster / genetics
  • Egg Proteins / genetics
  • Embryology
  • Female
  • Gene Expression Regulation*
  • Insect Hormones / metabolism
  • Molecular Sequence Data
  • Mutation
  • Oocytes / physiology
  • Ovary / cytology
  • Ovary / physiology*
  • Protein Binding
  • Protein Biosynthesis*
  • Proteins / genetics
  • RNA, Messenger / biosynthesis
  • RNA-Binding Proteins / genetics
  • RNA-Binding Proteins / metabolism*
  • Regulatory Sequences, Nucleic Acid


  • Drosophila Proteins
  • Egg Proteins
  • Insect Hormones
  • Proteins
  • RNA, Messenger
  • RNA-Binding Proteins
  • bru1 protein, Drosophila
  • exu protein, Drosophila
  • osk protein, Drosophila
  • nos protein, Drosophila