Glycobiology Advance Access published online on December 15, 2006
Glycobiology, doi:10.1093/glycob/cwl077
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Significant decrease of 
1,3-linked fucose is associated with increase in 6-sulfated N-acetylglucosamine in peripheral node addressin of FucT-VII deficient mice exhibiting diminished lymphocyte homing
2 Glycobiology Program, Cancer Research Center, Burnham Institute for Medical Research, La Jolla, California 92037
3 Department of Pathology, Case Western Reserve University School of Medicine, Cleveland, Ohio 44106
1 To whom correspondence should be addressed: Minoru Fukuda, Burnham Institute for Medical Research, 10901 North Torrey Pines Road, La Jolla, CA 92037; Tel no. 858-767-3144; Fax no. 858-646-3193; E-mail: minoru{at}burnham.org
Received on May 24, 2006; revised on December 1, 2006; accepted on December 1, 2006
Lymphocyte homing is mediated by binding of L-selectin on lymphocytes to L-selectin ligands present on high endothelial venules (HEV) of peripheral and mesenteric lymph nodes. L-selectin ligands are specific O-linked carbohydrates, 6-sulfo sialyl Lewis X, composed of sialylated, fucosylated, and sulfated glycans. Abrogation of fucosyltransferase-VII (FucT-VII) results in almost complete loss of lymphocyte homing, but carbohydrate structural analyses have not been carried on these mice. To determine if functional losses seen in FucT-VII null mice are caused by structural changes in carbohydrates, we elucidated the carbohydrate structure of GlyCAM-1, a major L-selectin counter-receptor. Our results show that most 
1,3-fucosylated structures in 6-sulfo sialyl Lewis X are absent, and 6-sulfo N-acetyllactosamine is increased in the mutant mice. Surprisingly, the amount of 6’-sulfated galactose, which bound to Sumbucus nigra agglutinin-column was also increased. We found that structures of those oligosaccharides containing 6’-sulfated galactose are almost identical to those synthesized by keratan sulfate sulfotransferase (KSST). We then showed that overexpression of KSST suppresses expression of sialyl Lewis X on Chinese hamster ovary (CHO) cells engineered to express sialyl Lewis X. Moreover, KSST expression in those cells suppressed lymphocyte rolling compared to mock-transfected CHO cells expressing 6-sulfo sialyl Lewis X. 6’-sulfo sialyl Lewis X cannot be found in GlyCAM-1 from CHO cells expressing both KSST and FucT-VII nor in GlyCAM-1 from HEV of mice. These results combined together suggest that KSST competes with FucT-VII for the same acceptor substrate and down-regulates the synthesis of L-selectin ligand by inhibiting 1,3-fucosylation.
Key words: L-selectin ligands / high endothelial venules / GlyCAM-1 / mucin-type O-glycans / FucT-VII null mice / 6’-sulfated galactose
4 Present address: Pathology Division, National Cancer Center Research Institute, 5-1-1, Tsukiji, Tokyo, 104-10045 Japan.
5 Present address: School of Pharmaceutical Science, University of Shizuoka, Shizuko, 422-8526 Japan.