brother of rhomboid, a rhomboid-related gene expressed during early Drosophila oogenesis, promotes EGF-R/MAPK signaling

Dev Biol. 2000 Oct 15;226(2):255-66. doi: 10.1006/dbio.2000.9851.


The Drosophila rhomboid (rho) gene participates in localized activation of EGF-receptor signaling in various developmental settings. The Rhomboid protein has been proposed to promote presentation and/or processing of the membrane-bound Spitz (mSpi) EGF-related ligand to generate an active diffusible form of the ligand. Here, we report on a new rhomboid-related gene identified by sequence similarity searching that we have named brother of rhomboid (brho). In contrast to rho, which is expressed in complex patterns during many stages of development, brho appears to be expressed only during oogenesis. brho transcripts are present in early oocytes and abut posterior follicle cells which exhibit high levels of MAPK activation. brho, like rho, collaborates with Star to promote signaling through the EGF-R/MAPK pathway, and genetic evidence indicates that Brho can activate both the mSpi and the Grk precursor EGF ligands in the wing. We propose that endogenous brho may activate the oocyte-specific Gurken ligand and thereby participate in defining posterior cell fates in the early follicular epithelium.

Publication types

  • Comparative Study
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Drosophila Proteins*
  • Drosophila melanogaster / embryology
  • Drosophila melanogaster / genetics*
  • Drosophila melanogaster / growth & development
  • Embryo, Nonmammalian / metabolism
  • Enzyme Activation
  • Epidermal Growth Factor*
  • ErbB Receptors / physiology*
  • Female
  • Gene Expression Regulation, Developmental*
  • Insect Proteins / biosynthesis
  • Insect Proteins / genetics*
  • Insect Proteins / physiology
  • Larva / metabolism
  • MAP Kinase Signaling System / genetics*
  • Membrane Proteins / genetics
  • Membrane Proteins / physiology
  • Molecular Sequence Data
  • Multigene Family
  • Oocytes / metabolism
  • Oogenesis / genetics*
  • Oogenesis / physiology
  • Ovarian Follicle / cytology
  • Ovarian Follicle / metabolism
  • Phosphoproteins / physiology
  • Phylogeny
  • Sequence Alignment
  • Sequence Homology, Amino Acid
  • Transcription, Genetic
  • Transforming Growth Factor alpha*
  • Transforming Growth Factors / physiology
  • Wings, Animal / embryology


  • Drosophila Proteins
  • Insect Proteins
  • Membrane Proteins
  • Phosphoproteins
  • Rho protein, Drosophila
  • S protein, Drosophila
  • Stet protein, Drosophila
  • Transforming Growth Factor alpha
  • grk protein, Drosophila
  • steroidogenic acute regulatory protein
  • spi protein, Drosophila
  • Epidermal Growth Factor
  • Transforming Growth Factors
  • ErbB Receptors