XBX-1 encodes a dynein light intermediate chain required for retrograde intraflagellar transport and cilia assembly in Caenorhabditis elegans.
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.
Schafer
Jenny C
JC
Department of Cell Biology, University of Alabama at Birmingham Medical Center, 35294, USA.
Haycraft
Courtney J
CJ
Thomas
James H
JH
Yoder
Bradley K
BK
Swoboda
Peter
P
D000818:Animals; D030801:Animals, Genetically Modified; D017173:Caenorhabditis elegans / Q000235:genetics / Q000378:metabolism*; D002923:Cilia / Q000378:metabolism*; D004398:Dyneins / Q000235:genetics / Q000378:metabolism*; D005407:Flagella / Q000378:metabolism*; D005786:Gene Expression Regulation; D017930:Genes, Reporter; D020409:Molecular Motor Proteins / Q000378:metabolism*; D017384:Sequence Deletion
D020409:Molecular Motor Proteins; D004398:Dyneins