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Journal of Biomedicine and Biotechnology
Volume 2011 (2011), Article ID 560850, 8 pages
http://dx.doi.org/10.1155/2011/560850
Research Article

Alpha 1,3-Galactosyltransferase Deficiency in Pigs Increases Sialyltransferase Activities That Potentially Raise Non-Gal Xenoantigenicity

1Department of Animal Biotechnology, Konkuk University, Seoul 143-701, Republic of Korea
2Department of Animal Science, College of Natural Science, Konkuk University, Chung-ju 380-701, Republic of Korea
3Division of Animal Life Science, College of Animal Bioscience & Technology, Konkuk University, Seoul 143-701, Republic of Korea

Received 29 May 2011; Revised 29 July 2011; Accepted 15 August 2011

Academic Editor: Saulius Butenas

Copyright © 2011 Jong-Yi Park et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

We examined whether deficiency of the GGTA1 gene in pigs altered the expression of several glycosyltransferase genes. Real-time RT-PCR and glycosyltransferase activity showed that 2 sialyltransferases [α2,3-sialyltransferase (α2,3ST) and α2,6-sialyltransferase (α2,6ST)] in the heterozygote GalT KO liver have higher expression levels and activities compared to controls. Enzyme-linked lectin assays indicated that there were also more sialic acid-containing glycoconjugate epitopes in GalT KO livers than in controls. The elevated level of sialic-acid-containing glycoconjugate epitopes was due to the low level of α-Gal in heterozygote GalT KO livers. Furthermore, proteomics analysis showed that heterozygote GalT KO pigs had a higher expression of NAD+-isocitrate dehydrogenase (IDH), which is related to the CMP-N-acetylneuraminic acid hydroxylase (CMAH) enzyme reaction. These findings suggest the deficiency of GGTA1 gene in pigs results in increased production of N-glycolylneuraminic acid (Neu5Gc) due to an increase of α2,6-sialyltransferase and a CMAH cofactor, NAD+-IDH. This indicates that Neu5Gc may be a critical xenoantigen. The deletion of the CMAH gene in the GalT KO background is expected to further prolong xenograft survival.