title: Molecular characterization and expression analyses of ST8Sia II and IV in piglets during postnatal development: lack of correlation between transcription and posttranslational levels.
abstract: The two mammalian α2,8-polysialyltransferases (polyST's), ST8Sia II (STX) and ST8Sia IV (PST), catalyze synthesis of the α2-8-linked polysialic acid (polySia) glycans on neural cell adhesion molecules (NCAMs). The objective of this study was to clone the coding sequence of the piglet ST8Sia II and determine the mRNA expression levels of ST8Sia II, ST8Sia IV, NCAM and neuropilin-2 (NRP-2), also a carrier protein of polySia, during postnatal development. The amino acid sequence deduced from the coding sequence of ST8Sia II was compared with seven other mammalian species. Piglet ST8Sia II was highly conserved and shared 67.8% sequence identity with ST8Sia IV. Genes coding for ST8Sia II and IV were differentially expressed and distinctly different in neural and non-neural tissues at postnatal days 3 and 38. Unexpectedly, the cellular levels of mRNA coding for ST8Sia II and IV showed no correlation with the posttranslational level of polySia glycans in different tissues. In contrast, mRNA abundance coding for NCAM and neuropilin-2 correlated with expression of ST8Sia II and IV. These findings show that the cellular abundance of ST8Sia II and IV in postnatal piglets is regulated at the level of translation/posttranslation, and not at the level of transcription, a finding that has not been previously reported. These studies further highlight differences in the molecular mechanisms controlling polysialylation in adult rodents and neonatal piglets.
authors.affiliation: School of Medicine, Xiamen University, Xiamen City, 361005, China.
authors.forename: Xi
authors.initials: X
authors.lastname: Zhu
authors.affiliation: School of Medicine, Xiamen University, Xiamen City, 361005, China.
authors.forename: Yue
authors.initials: Y
authors.lastname: Chen
authors.affiliation: School of Medicine, Xiamen University, Xiamen City, 361005, China.
authors.forename: Nai
authors.initials: N
authors.lastname: Zhang
authors.affiliation: School of Medicine, Xiamen University, Xiamen City, 361005, China.
authors.forename: Zhiqiang
authors.initials: Z
authors.lastname: Zheng
authors.affiliation: School of Medicine, Xiamen University, Xiamen City, 361005, China.
authors.forename: Fengjun
authors.initials: F
authors.lastname: Zhao
authors.affiliation: School of Medicine, Xiamen University, Xiamen City, 361005, China.
authors.forename: Ni
authors.initials: N
authors.lastname: Liu
authors.affiliation: School of Medicine, Xiamen University, Xiamen City, 361005, China.
authors.forename: Chunlong
authors.initials: C
authors.lastname: Lv
authors.affiliation: School of Medicine, Xiamen University, Xiamen City, 361005, China. fatroy@ucdavis.edu.|Department of Biochemistry and Molecular Medicine, University of California School of Medicine, Davis, CA, 95616, USA. fatroy@ucdavis.edu.
authors.forename: Frederic A
authors.initials: FA
authors.lastname: Troy
authors.affiliation: School of Medicine, Xiamen University, Xiamen City, 361005, China. biwang@csu.edu.au.|School of Animal & Veterinary Science, Charles Sturt University, Wagga Wagga, NSW, 2678, Australia. biwang@csu.edu.au.
authors.forename: Bing
authors.initials: B
authors.lastname: Wang
mesh_terms: D000818:Animals; D001921:Brain / Q000254:growth & development / Q000378:metabolism; D006031:Glycosylation; D008297:Male; D011499:Protein Processing, Post-Translational; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D012799:Sialyltransferases / Q000235:genetics / Q000378:metabolism*; D013552:Swine
chemical_list: D012333:RNA, Messenger; C046778:CMP-N-acetylneuraminate-poly-alpha-2,8-sialosyl sialyltransferase; D012799:Sialyltransferases; C517012:ST8Sia IV protein, swine
keywords: NCAM; Neuropilin-2; Piglet ST8Sia II & IV; Polysialic acid; Posttranslation regulation; α2,8-polysialyltransferases