Aberration of Serum and Tissue N-Glycans in Mouse β1,4-GalT1 Y286L Mutant Variants

• Published in: Glycoconjugate journal Vol. 37; no. 6; pp. 767 - 775
• Main Authors: Cao, Ran, Zhang, Tian-Chan, Chen, Ya-Ran, Cao, Cui, Chen, Huan, Huang, Yi-Fan, Fujita, Morihisa, Liu, Li, Voglmeir, Josef
• Format: Journal Article
• Language: English
• Published: New York Springer US 01.12.2020; Springer Nature B.V
• Subjects: Biochemistry; Biomedical and Life Sciences; CRISPR; Cross-breeding; D-Galactosamine; Glycosylation; Glycosyltransferase; Intestine; Kidneys; Lactose; Leucine; Life Sciences; Mammary gland; Mutants; N-Acetylgalactosamine; N-glycans; Original Article; Pathology; Polysaccharides; Spleen; Substrate specificity; Tyrosine; glycosylation; B4GALT1; Sialylation; Galactosylation; Tissue-specific; Tissue-specific N-glycosylation
• ISSN: 0282-0080; 1573-4986; 1573-4986
• DOI: 10.1007/s10719-020-09946-8

β1,4-GalT1 is a type II membrane glycosyltransferase. It catalyzes the production of lactose in the lactating mammary gland and is supposedly also involved in the galactosylation of terminal GlcNAc of complex-type N -glycans. In-vitro studies of the bovine β4Gal-T1 homolog showed that replacing a single residue of tyrosine with leucine at position 289 alters the donor substrate specificity from UDP-Gal to UDP- N -acetyl-galactosamine (UDP-GalNAc). The effect of this peculiar change in β1,4GalT1 specificity was investigated in-vivo , by generating biallelic Tyr286Leu β1,4GalT1 mice using CRISPR/Cas9 and crossbreeding. Mice bearing this mutation showed no appreciable defects when compared to wild-type mice, with the exception of biallelic female B4GALT1 mutant mice, which were unable to produce milk. The detailed comparison of wild-type and mutant mice derived from liver, kidney, spleen, and intestinal tissues showed only small differences in their N -glycan pattern. Comparable N -glycosylation was also observed in HEK 293 wild-type and knock-out B4GALT1 cells. Remarkably and in contrast to the other analyzed tissue samples, sialylation and galactosylation of serum N -glycans of biallelic Tyr286Leu GalT1 mice almost disappeared completely. These results suggest that β1,4GalT1 plays a special role in the synthesis of serum N -glycans. The herein described Tyr286Leu β1,4GalT1 mutant mouse model may, therefore, prove useful in the investigation of the mechanism which regulates tissue-dependent galactosylation.