Sialyltransferases expression

Curiously, this chemical modification of Gonococci living in the host is possible by a sialyltransferase expressed by the bacterium itself and the sialic acid donor substrate, CMP-Neu5Ac, produced by the host. The properties of the sialyltransferase extracted from the bacteria have been reported [974]. It would be very interesting to compare the primary structure of this enzyme with those of host sialyltransferases. This mechanism is different from that used by trypanosomes for sialylation, although in both cases sialic acids are acquired from the host. 

Baum, L.G., Derbin, K., Perillo, N.L., Wu, T., Pang, M. and Uittenbogaart, C. Characterization of terminal sialic acid linkages on human thymocytes. Correlation between lectin-binding phenotype and sialyltransferase expression. J. Biol. Chem., 271, 10793-10799 (1996). 

Regulation of sialyltransferase expression by post-transcriptional mechanisms remains largely unexplored. For ST6Gal I, differential promoter usage results in divergent 5 -imtranslated regions in the mRNAs. In vitro translation experiments... 

Haraguchi, M., Yamashiro, S., Yamamoto, A., Fumkawa, K., Takamiya, K., Lloyd, K. O., Shiku, H., and Fumkawa, K., 1994, Isolation ofGD3 synthasegene by expression cloning ofGM3 a-2,8-sialyltransferase cDNA using anti-GD2 monoclonal antibody. Proc. Natl. Acad. Sci. USA 91 10455-10459. 

As an alternative to chemical sialylations, glycosyl transferases have been used to accomplish sialylations, particularly of N-linked glycopeptide building blocks (see also Section 6.3.1.1.5). The 2,3- and 2,6-sialyltransferases have been easily expressed in preparative amounts. Their use in glycopeptide building block synthesis is described in Section 6.3.3.6. 

Kono M, Takashima S, Liu H, Inoue M, Kojima N, Lee YC, Hamamoto T, Tsuji S. Molecular cloning and functional expression of a fifth-type alpha 2,3-sialyltransferase (mST3Gal V GM3 synthase). Biochem. Biophys. Res. Commun. 1998 253-175. Daniotti JL, Martina JA, Giraudo CG, Zurita AR, Maccioni HJ. GM3 alpha2,8-sialyltransferase (GD3 synthase) protein characterization and sub-golgi location in CHO-Kl cells. J. Neurochem. 2000 74 1711-1720. 

Lee YC, Kurosawa N, Hamamoto T, Nakaoka T, Tsuji S (1993) Molecular cloning and expression of Gal/il,3GalNAc a2,3-sialyltransferase from mouse brain. Eur J Biochem 216 377-385... 

Kitagawa H, Paulson JC (1994) Differential expression of five sialyltransferase genes in human tissues. J Biol Chem 269 17872-17878... 

K, Nagai Y, Sanai Y (1994) Expression cloning of a CMP-NeuAc NeuAc 0 2-3Gal jSl-4Glc jll-l Cer 0 2,8-sialyltransferase (GD3 synthase) from human melanoma cells. Proc Natl Acad Sci USA 91 7952-7956... 

Kono M, Yoshida Y, Kojima N, Tsuji S (1996) Molecular cloning and expression of a fiffii type of 0 2,8-sialyltransferase (ST8Sia V) Its substrate specificity is similar to that of SAT-V/III, which synthesize GDlc, GTla, GQlb and GT3. J Biol Chem 271 29366-29371... 

Kurosawa N, Kojima N, Inoue M, Hamamo-to T, Tsuji S (1994) Cloning and expression of Gal l,3GalNAc-sp ecific GalNAc a2,6-sialyltransferase. J Biol Chem 269 19048-19053... 

Fukumoto S, Miyazaki H, Goto G, Urano T, Furukawa K, Furukawa K (1999) Expression cloning of mouse cDNA of CMP-NeuAc Lactosylceramide a2,3-sialyltransferase, an enzyme that initiates the synthesis of ganglio-sides. J Biol Chem 274 9271-9276... 

A second layer of complexity that both confounds and increases the potential ability of MOE experiments to modulate biological responses lies in the various glycosidic linkages of sialic acid ( Fig. 6). In humans, which only express a subset of these linkages (a-2,3-, a-2,6-, and a-2,8-), 20 sialyltransferases (STs [51]) work in parallel to install sialic acids onto glycoproteins and lipids. The structural importance of each linkage is illustrated by binding preference... 

Lee EU, Roth J Paulson JC (1989) Alteration of terminal glycosylation sequences on N-linked oligosaccharides of Chinese hamster ovary cells by expression of beta-galactosidase alpha 2,6-sialyltransferase. Journal of Biological Chemistry 264 13848-13855. 

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