The Caenorhabditis elegans gene unc-76 and its human homologs define a new gene family involved in axonal outgrowth and fasciculation

The Caenorhabditis elegans gene unc-76 and its human homologs define a new gene family involved in axonal outgrowth and fasciculation

Laird Bloom and
H. Robert Horvitz*

Howard Hughes Medical Institute, Department of Biology, Room 68-425, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139

Abstract

The gene unc-76 (unc, uncoordinated) is necessary for normal axonal bundling and elongation within axon bundles in the nematode Caenorhabditis elegans. The UNC-76 protein and two human homologs identified as expressed sequence tags are not similar to previously characterized proteins and thus represent a new protein family. At least one of these human homologs can function in C. elegans, suggesting that it, like UNC-76, acts in axonal outgrowth. We propose that the UNC-76 protein, which is found in cell bodies and processes of all neurons throughout development, either has a structural role in the formation and maintenance of axonal bundles or transduces signals to the intracellular machinery that regulates axonal extension and adhesion.

Footnotes

↵ * To whom reprint requests should be addressed. e-mail: horvitz{at}mit.edu.
H. Robert Horvitz
Data deposition: The sequences reported in this paper have been deposited in the GenBank database [accession nos.: unc-76 genomic DNA, U28153U28153; unc-76 cDNA clones, U60058U60058 (p76-c7) and U60059U60059 (p76-c4); FEZ1, U60060U60060; FEZ1-T, U60062U60062; and FEZ2, U60061U60061].
ABBREVIATIONS:

GABA,

γ-aminobutyric acid;

HSN,

hermaphrodite-specific neuron