H. Kimura et al., DISTINCT SUBSTRATE SPECIFICITIES OF 5 HUMAN ALPHA-1,3-FUCOSYL-TRANSFERASES FOR IN-VIVO SYNTHESIS OF THE SIALYL-LEWIS-X AND LEWIS-X EPITOPES, Biochemical and biophysical research communications, 237(1), 1997, pp. 131-137
Five different human alpha-1,3-fucosyltransferase genes, the Fuc-TIII,
Fuc-TIV, Fuc-TV, Fuc-TVI and Fuc-TVII genes, have been cloned to date
. We transfected HeLa cells and Namalwa cells with each of the five di
fferent genes, and established a series of stable cloned transformant
cells. Thin-layer chromatography immunostaining analysis revealed that
all five enzymes were able to synthesize sialyl Lewis x (sLe(x)) epit
opes on glycolipids in HeLa cells, but each enzyme showed a different
preference as to the carbohydrate chain length on glycolipids as accep
tor substrates. Fuc-TIII and Fuc-TV showed very similar patterns of sL
e(x) positive bands, which indicated that the enzymes have similar acc
eptor substrate specificities. Fuc-TVI exhibited a little different pa
ttern from those of the former two enzymes. Fuc-TIV and Fuc-TVII showe
d similarity in the positive bands, however, their patterns were quite
different from those of the former three enzymes. Four enzymes except
for Fuc-TVII were able to synthesize the Lewis x (Le(x)) epitope on g
lycolipids in HeLa cells. Fuc-TV alone showed a little different patte
rn of Le(x) positive bands from those of the other three enzymes. Flow
cytometric analysis of HeLa cells and Namalwa cells again demonstrate
d the similar specificities of Fuc-TIII and Fuc-TV. They exhibited sim
ilar stronger staining with FH6 (anti-sLe(x)) antibodies than that wit
h the other enzymes. A phylogenetic tree of the five enzymes construct
ed using the neighbor-joining method showed good agreement with the si
milarities in the enzyme substrate specificity. (C) 1997 Academic Pres
s.