Lemon encodes an unusual receptor protein-tyrosine kinase expressed during gametogenesis in Hydra

Academic Article


  • In a screen for receptor protein-tyrosine kinase (RTK) genes expressed during gametogenesis in the cnidarian Hydra vulgaris, we isolated a cDNA encoding Lemon, an RTK with unusual features. Lemon is orthologous to Drosophila Dtrk, chicken Klg, and human colon carcinoma kinase-4. These genes constitute an RTK class characterized by a conserved transmembrane sequence, the presence of extracellular immunoglobulin-like repeats, and the absence of the DFG motif in the kinase domain. We provide evidence that Lemon is a component of an unusual RTK signal transduction mechanism that may involve transmembrane domain-mediated interactions and may not be dependent on its own catalytic activity. Lemon transcription is dynamically regulated in interstitial cells during asexual budding and gametogenesis. Transcriptional up-regulation occurs early in spermatogenesis and oogenesis concurrent with the local accumulation of interstitial cells in the body column of sexual polyps. (C) 2000 Academic Press.
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    Digital Object Identifier (doi)

    Author List

  • Miller MA; Steele RE
  • Start Page

  • 286
  • End Page

  • 298
  • Volume

  • 224
  • Issue

  • 2