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Involvement of the alpha2,8-polysialyltransferases II/STX and IV/PST in the biosynthesis of polysialic acid chains on the O-linked glycoproteins in rainbow trout ovary.
- Source :
-
Journal of biochemistry [J Biochem] 2006 Nov; Vol. 140 (5), pp. 687-701. Date of Electronic Publication: 2006 Oct 05. - Publication Year :
- 2006
-
Abstract
- Polysialoglycoprotein (PSGP) in salmonid fish egg is a unique glycoprotein bearing alpha2,8-linked polysialic acid (polySia) on its O-linked glycans. Biosynthesis of the polySia chains is developmentally regulated and only occurs at later stage of oogenesis. Two alpha2,8-polysialyltransferases (alpha2,8-polySTs), PST (ST8Sia IV) and STX (ST8Sia II), responsible for the biosynthesis of polySia on N-glycans of glycoproteins, are known in mammals. However, nothing has been known about which alpha2,8-polySTs are involved in the biosynthesis of polySia on O-linked glycans in any glycoproteins. We thus sought to identify cDNA encoding the alpha2,8-polyST involved in polysialylation of PSGP. A clone for PST orthologue, rtPST, and two clones for the STX orthologue, rtSTX-ov and rtSTX-em, were identified in rainbow trout. The deduced amino acid sequence of rtPST shows a high identity (72-77%) to other vertebrate PSTs, while that of rtSTX-ov shows 92% identity with rtSTX-em and a significant identity (63-76%) to other vertebrate STXs. The rtPST exhibited the in vivo alpha2,8-polyST activity, although its in vitro activity was low. However, the rtSTXs showed no in vivo and very low in vitro activities. Interestingly, co-existence of rtPST and rSTX-ov in the reaction mixture synergistically enhanced the alpha2,8-polyST activity. During oogenesis, rtPST was constantly expressed, while the expression of rtSTX-ov was not increased until polySia chain is abundantly biosynthesized in the later stage. rtSTX-em was not expressed in ovary. These results suggest that the enhanced expression of rtSTX-ov under the co-expression with rtPST may be important for the biosynthesis of polySia on O-linked glycans of PSGP.
- Subjects :
- Amino Acid Sequence
Animals
Blotting, Northern
COS Cells
Chlorocebus aethiops
Female
Gene Expression
Male
Metabolic Networks and Pathways
Molecular Sequence Data
Oncorhynchus mykiss
Oogenesis physiology
Polysaccharides biosynthesis
Reverse Transcriptase Polymerase Chain Reaction
Sequence Alignment
Sialic Acids biosynthesis
Tissue Distribution
Transfection
Ovary enzymology
Sialoglycoproteins biosynthesis
Sialyltransferases metabolism
Subjects
Details
- Language :
- English
- ISSN :
- 0021-924X
- Volume :
- 140
- Issue :
- 5
- Database :
- MEDLINE
- Journal :
- Journal of biochemistry
- Publication Type :
- Academic Journal
- Accession number :
- 17023684
- Full Text :
- https://doi.org/10.1093/jb/mvj200