XBX-1 encodes a dynein light intermediate chain required for retrograde intraflagellar transport and cilia assembly in Caenorhabditis elegans

Mol Biol Cell. 2003 May;14(5):2057-70. doi: 10.1091/mbc.e02-10-0677. Epub 2003 Jan 26.

Abstract

Intraflagellar transport (IFT) is a process required for flagella and cilia assembly that describes the dynein and kinesin mediated movement of particles along axonemes that consists of an A and a B complex, defects in which disrupt retrograde and anterograde transport, respectively. Herein, we describe a novel Caenorhabditis elegans gene, xbx-1, that is required for retrograde IFT and shares homology with a mammalian dynein light intermediate chain (D2LIC). xbx-1 expression in ciliated sensory neurons is regulated by the transcription factor DAF-19, as demonstrated previously for genes encoding IFT complex B proteins. XBX-1 localizes to the base of the cilia and undergoes anterograde and retrograde movement along the axoneme. Disruption of xbx-1 results in cilia defects and causes behavioral abnormalities observed in other cilia mutants. Analysis of cilia in xbx-1 mutants reveals that they are shortened and have a bulb like structure in which IFT proteins accumulate. The role of XBX-1 in IFT was further confirmed by analyzing the effect that other IFT mutations have on XBX-1 localization and movement. In contrast to other IFT proteins, retrograde XBX-1 movement was detected in complex A mutants. Our results suggest that the DLIC protein XBX-1 functions together with the CHE-3 dynein in retrograde IFT, downstream of the complex A proteins.

Publication types

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

MeSH terms

  • Animals
  • Animals, Genetically Modified
  • Caenorhabditis elegans / genetics
  • Caenorhabditis elegans / metabolism*
  • Cilia / metabolism*
  • Dyneins / genetics
  • Dyneins / metabolism*
  • Flagella / metabolism*
  • Gene Expression Regulation
  • Genes, Reporter
  • Molecular Motor Proteins / metabolism*
  • Sequence Deletion

Substances

  • Molecular Motor Proteins
  • Dyneins