The Drosophila trio plays an essential role in patterning of axons by regulating their directional extension

Neuron. 2000 Apr;26(1):119-31. doi: 10.1016/s0896-6273(00)81143-5.


We identified the Drosophila trio gene, which encodes a Dbl family protein carrying two Dbl homology (DH) domains, each of which potentially activates Rho family GTPases. Trio was distributed along axons in the central nervous system (CNS) of embryos and was strongly expressed in subsets of brain regions, including the mushroom body (MB). Loss-of-function trio mutations resulted in the misdirection or stall of axons in embryos and also caused malformation of the MB. The MB phenotypes were attributed to alteration in the intrinsic nature of neurites, as revealed by clonal analyses. Thus, Trio is essential in order for neurites to faithfully extend on the correct pathways. In addition, the localization of Trio in the adult brain suggests its postdevelopmental role in neurite terminals.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Axons / physiology*
  • Central Nervous System / embryology*
  • Central Nervous System / physiology
  • Drosophila / genetics
  • Drosophila Proteins*
  • Growth Cones / physiology*
  • Guanine Nucleotide Exchange Factors*
  • Molecular Sequence Data
  • Neurites / physiology*
  • Oligochaeta / genetics
  • Phosphoproteins / genetics*
  • Phosphoproteins / physiology
  • Protein-Serine-Threonine Kinases / genetics*
  • Protein-Serine-Threonine Kinases / physiology


  • Drosophila Proteins
  • Guanine Nucleotide Exchange Factors
  • Phosphoproteins
  • Protein-Serine-Threonine Kinases
  • trio protein, Drosophila

Associated data

  • GENBANK/AB035419