The widespread effect of beta 1,4-galactosyltransferase on N-glycan processing.
We investigated beta 1,4-GalT (UDP-galactose: beta-d-N-acetylglucosaminide beta 1,4-galactosyltransferase) in terms of intracellular competition with GnT-IV (UDP-N-acetylglucosamine: alpha1,3-d-mannoside beta1,4-N-acetylglucosaminyltransferase) and GnT-V (UDP-N-acetylglucosamine: alpha1,6-d-mannoside beta 1,6-N-acetylglucosaminyltransferase). The beta 1,4-GalT-I gene was introduced into Chinese hamster ovary (CHO) cells producing human interferon (hIFN)-gamma (IM4/V/IV cells) and five clones expressing various levels of beta 1,4-GalT were isolated. As we previously reported, parental IM4/V/IV cells express high levels of GnT-IVa and -V and produce hIFN-gamma having primarily tetraantennary sugar chains. The branching of sugar chains on hIFN-gamma was suppressed in the beta 1,4-GalT-enhanced clones to a level corresponding to the intracellular activity of beta 1,4-GalT relative to GnTs. Moreover, the contents of hybrid-type and high-mannose-type sugar chains increased in these clones. The results showed that beta 1,4-GalT widely affects N-glycan processing by competing with GnT-IV, GnT-V, and alpha-mannosidase II in cells and also by some other mechanisms that suppress the conversion of high-mannose-type sugar chains to the hybrid type.
Fukuta
K
K
Life Science Laboratory, Mitsui Chemicals, Incorporated, 1144 Togo, Mobara, Chiba 297-0017, Japan. kazuhiro.fukuta@mitsui-chem.co.jp
Abe
R
R
Yokomatsu
T
T
Minowa
M T
MT
Takeuchi
M
M
Asanagi
M
M
Makino
T
T
D000818:Animals; D016466:CHO Cells; D002240:Carbohydrate Sequence; D002851:Chromatography, High Pressure Liquid; D006224:Cricetinae; D006801:Humans; D007371:Interferon-gamma / Q000096:biosynthesis / Q000737:chemistry / Q000235:genetics; D008358:Mannose / Q000737:chemistry; D008361:Mannosidases / Q000378:metabolism; D008969:Molecular Sequence Data; D017351:N-Acetylglucosaminyltransferases / Q000378:metabolism; D009237:N-Acetyllactosamine Synthase / Q000235:genetics / Q000378:metabolism*; D011134:Polysaccharides / Q000737:chemistry / Q000378:metabolism*; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D043323:alpha-Mannosidase
D011134:Polysaccharides; D011994:Recombinant Proteins; D007371:Interferon-gamma; D017351:N-Acetylglucosaminyltransferases; C038111:alpha-1,3-mannosylglycoprotein beta-1,4-N-acetylglucosaminyltransferase; C052254:alpha-1,6-mannosylglycoprotein beta 1,6-N-acetylglucosaminyltransferase; D009237:N-Acetyllactosamine Synthase; D008361:Mannosidases; D043323:alpha-Mannosidase; D008358:Mannose