Three proteins involved in Caenorhabditis elegans vulval invagination are similar to components of a glycosylation pathway

Three proteins involved in Caenorhabditis elegans vulval invagination are similar to components of a glycosylation pathway

Tory Herman and
H. Robert Horvitz*

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

Contributed by H. Robert Horvitz

Abstract

We have molecularly analyzed three genes, sqv-3 , sqv-7, and sqv-8, that are required for wild-type vulval invagination in Caenorhabditis elegans. The predicted SQV-8 protein is similar in sequence to two mammalian β(1,3)-glucuronyltransferases, one of which adds glucuronic acid to protein-linked galactose-β(1,4)-N-acetylglucosamine. SQV-3 is similar to a family of glycosyltransferases that includes vertebrate β(1,4)-galactosyltransferases, which create galactose-β(1,4)-N-acetylglucosamine linkages. One model is therefore that SQV-8 uses a SQV-3 product as a substrate. SQV-7 is similar to members of a family of nucleotide-sugar transporters. The sqv genes therefore are likely to encode components of a conserved glycosylation pathway that assembles a C. elegans carbohydrate moiety, the absence of which perturbs vulval invagination.

Footnotes

↵ * To whom reprint requests should be addressed. e-mail: horvitz{at}mit.edu.
Data deposition: The sequences reported in this paper have been submitted to the GenBank database [accession nos. AJ005864 (sqv-8 cDNA), AJ005866 (human cDNA 132056 encoding a SQV-7-like protein), and AJ005867 (sqv-3 cDNA)].
ABBREVIATIONS:

GlcA,

glucuronic acid;

Gal,

galactose;

GlcAT-P,

rat β(1,3)-glucuronyltransferase;

GlcAT-I,

human β(1,3)-glucuronyltransferase;

GalT,

human β(1,4)-galactosyltransferase;

GlcNAcT,

snail β(1,4)-N-acetylglucosaminyltransferase