K. Uehara et J. Thelu, Stage- and tissue-specific expression of a beta-1,4-galactosyltransferase in the embryonic epidermis, IN VITRO-AN, 37(9), 2001, pp. 613-617
Changes in oligosaccharide structures of glycoconjugates have been observed
, and are postulated to have key roles in embryonic development and differe
ntiation. N-Acetylglucosamine (GlcNAc) beta -1,4-galactosyltransferase (bet
a 4GalT) AKI showed different expression patterns in time and space, and di
fferent enzymatic activity from the other known family members, The epiderm
is of mouse embryo included a high level of AKI activities. which transferr
ed galactose (Gal) to endogenous glycoprotein (molecular weight 130 kDa) (G
P130). The maximum activity was for 13.5-d postcoitum embryos. Specific ant
ibody against AKI inhibited 81% of GlcNAc beta 4GalT activities, which indi
cates that AKI represents the major part of the embryonic epidermis enzymes
. AKI shows 2.2 times higher galactosyltransferase activity toward Gal-acce
ptor glucose with alpha -lactalbumin (alpha -LA) than toward GlcNAc without
alpha -LA. AKI is also expressed in mouse melanoma and leukemia cell lines
and in human basal cell carcinoma specimens. The GP130 Gal acceptor once g
alactosylated by AKI may be directly involved in epidermal differentiation
and oncogenesis.