title: Molecular mechanisms involved in transcriptional activation of the human Sia-alpha2,3-Gal-beta1,4-GlcNAc-R:alpha2,8-sialyltransferase (hST8Sia III) gene induced by KCl in human glioblastoma cells.
abstract: In the present study, we have shown that KCl known as an inducer for differentiation of neuronal cells increases the human Sia-alpha2,3-Gal-beta1,4-GlcNAc-R:alpha2,8-sialyltransferase (hST8Sia III) gene transcription via phosphoinositide 3 kinase (PI-3K) in glioblastoma U-87MG cells. The induction of hST8Sia III by KCl is regulated at the transcriptional level in a dose- and time-dependent manner as evidenced by reverse transcription-polymerase chain reaction (RT-PCR). To elucidate the mechanism underlying the regulation of hST8Sia III gene expression in U-87MG cells induced by KCl, we characterized the promoter region of the hST8Sia III gene. Functional analysis of the 5'-flanking region of the hST8Sia III gene by the transient expression method showed that the -1194 to -816 region functions as the KCl-inducible promoter in U-87MG cells. Furthermore, as evidenced by Western blot analysis and RT-PCR, KCl-induced expression of hST8Sia III gene was dependent on the PI-3K signal transduction pathway during the neuronal differentiation of U-87 cells, as an increase in beta-tubulin III known as a neuronal differentiation marker was observed. In KCl-depolarization on U-87 cells, the PI-3K-dependent promoter activation at the -1194 to -816 region up-regulated expression of hST8Sia III gene. These results suggest that the expression of hST8Sia III gene via the PI-3K signaling pathway is enhanced during KCl-induced differentiation of U-87 cells by increasing expression of beta-tubulin III.
authors.affiliation: Department of Biotechnology, Dong-A University, Busan 604-714, Republic of Korea.
authors.forename: Seok-Jo
authors.initials: SJ
authors.lastname: Kim
authors.forename: Tae-Wook
authors.initials: TW
authors.lastname: Chung
authors.forename: Un-Ho
authors.initials: UH
authors.lastname: Jin
authors.forename: Seok-Jong
authors.initials: SJ
authors.lastname: Suh
authors.forename: Young-Choon
authors.initials: YC
authors.lastname: Lee
authors.forename: Cheorl-Ho
authors.initials: CH
authors.lastname: Kim
mesh_terms: D024506:5' Flanking Region; D001483:Base Sequence; D002454:Cell Differentiation / Q000235:genetics; D015971:Gene Expression Regulation, Enzymologic; D005909:Glioblastoma; D006801:Humans; D008969:Molecular Sequence Data; D009474:Neurons / Q000166:cytology / Q000187:drug effects / Q000201:enzymology*; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism; D011189:Potassium Chloride / Q000494:pharmacology; D011401:Promoter Regions, Genetic / Q000187:drug effects; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism; D012799:Sialyltransferases / Q000235:genetics*; D024363:Transcription Initiation Site; D014158:Transcription, Genetic / Q000187:drug effects; D015533:Transcriptional Activation; D014404:Tubulin / Q000378:metabolism
chemical_list: C498585:TUBB3 protein, human; D014404:Tubulin; D011189:Potassium Chloride; C094133:Sia(alpha2,3)Gal(beta1,4)GlcNAc alpha-2,8-sialyltransferase; D012799:Sialyltransferases; D019869:Phosphatidylinositol 3-Kinases; D051057:Proto-Oncogene Proteins c-akt