Glycobiology Advance Access originally published online on December 15, 2006
Glycobiology 2007 17(3):277-293; doi:10.1093/glycob/cwl077
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Significant decrease in 
1,3-linked fucose in association with increase in 6-sulfated N-acetylglucosamine in peripheral lymph node addressin of FucT-VII-deficient mice exhibiting diminished lymphocyte homing
2 Glycobiology Program, Cancer Research Center, Burnham Institute for Medical Research, La Jolla, CA 92037
3 Department of Pathology, Case Western Reserve University School of Medicine, Cleveland, OH 44106
1 To whom correspondence should be addressed; Tel: +1-858-646-3144; Fax: +1-858-646-3193; 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 with 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 structural analysis of carbohydrates has not been carried out on FucT-VII null mice. To determine whether 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 (Gal) that bound to Sumbucus nigra agglutinin column was also increased. We found that structures of those oligosaccharides containing 6'-sulfated Gal are almost identical to those synthesized by keratan sulfate sulfotransferase (KSST). We then showed that overexpression of KSST suppresses the 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 with mock-transfected CHO cells expressing 6-sulfo sialyl Lewis X. 6'-Sulfo sialyl Lewis X can neither be found in GlyCAM-1 from CHO cells expressing both KSST and FucT-VII nor be found in GlyCAM-1 from HEV of mice. These results combined together suggest that KSST competes with FucT-VII for the same acceptor substrate and downregulates 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, 104-0045 Japan
5 Present address: School of Pharmaceutical Sciences, University of Shizuoka, Shizuoka, 422-8526 Japan