Regulation of expression of β‐galactoside α2, 6‐sialyltransferase in a rat tumor, Zajdela ascitic hepatoma
TL;DR: In this paper, the authors studied the regulation of expression of β-galactoside α2, 6-sialyltransferase in a rat tumor, the Zajdela ascitic hepatoma.
About: This article is published in FEBS Letters.The article was published on 1993-02-08 and is currently open access. It has received 6 citations till now. The article focuses on the topics: Sialyltransferase & Sialic acid.
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200 citations
TL;DR: The cognate oligosaccharide structure, NeuAcα,6Galβ1,4GIcNAc, is widely distributed among tissues and is involved in biological processes such as the regulation of the immune response and the progression of colon cancer.
Abstract: Sialylation represents one of the most frequently occurring terminations of the oligosaccharide chains of glycoproteins and glycolipids. Sialic acid is commonly found α,3- or α,6-linked to galactose (Gal), α,6-linked to N-acetylgalactosamine (GalNAc) or α,8-linked to another sialic acid. The biosynthesis of the various linkages is mediated by the different members of the sialyltransferase family. The addition of sialic acid in α,6-linkage to the galactose residue of lactosamine (type 2 chains) is catalyzed by β-galactoside α,6-sialyltransferase (ST6Gal.I). Although expressed by a single gene, this enzyme shows a complex pattern of regulation which allows its tissue- and stage-specific modulation. The cognate oligosaccharide structure, NeuAcα,6Galβ1,4GIcNAc, is widely distributed among tissues and is involved in biological processes such as the regulation of the immune response and the progression of colon cancer. This review summarizes the current knowledge on the biochemistry of ST6Gal.I and on the functional role of the sialyl-α,6-lactosaminyl structure.
103 citations
TL;DR: Investigation of the expression of ST6Gal.I and its product, the alpha2,6-sialylated lactosamine, in normal human liver, hepatocarcinoma (HCC), and cirrhosis found that both ST6 Gal.I activity and mRNA can undergo up- or down-regulation in different HCC patients.
Abstract: beta-Galactoside alpha2,6-sialyltransferase (ST6Gal.I) mediates the addition of alpha2,6-linked sialic acid to glycoproteins. ST6Gal.I is strongly expressed by the liver and is up-regulated in several cancers, but little is known of its regulation in human liver diseases. We have investigated the expression of ST6Gal.I and its product, the alpha2,6-sialylated lactosamine, in normal human liver, hepatocarcinoma (HCC), and cirrhosis. We found that both ST6Gal.I activity and mRNA can undergo up- or down-regulation in different HCC patients. At the mRNA level, the groups of specimens showing the highest expression were HCC of grade 2, HCC developed without preexisting cirrhosis, and HCC of male patients. The lectin from Sambucus nigra (SNA) reveals a significative overexpression of alpha2,6-sialylated glycoconjugates in HCC tissue homogenates and their intracellular accumulation in HCC histological sections, even though in a few cases the extent of alpha2,6-sialylation dramatically decreases. Transcription of the gene occurs through at least two different promoters, resulting in two differentially expressed mRNA species. RNA in situ hybridization reveals that the ST6Gal.I mRNA can be expressed at a quantitatively heterogeneous level among the neoplastic cells. Neither ST6Gal.I expression nor alpha2,6-sialylation are altered in cirrhosis. These data indicate that neoplastic transformation but not cirrhosis can alter the process of alpha2,6-sialylation of liver glycoproteins.
74 citations
TL;DR: The existence of a third transcript in the hepatoma cell-line HepG2 is demonstrated, controlled by a promoter region which efficiently supports transcription in HepG1 cells, and which harbours putative binding sites for liver-enriched and acute phase inducible transcription factors.
38 citations
TL;DR: Glycan expression is likely to have a major impact on morphogenesis during ontogenesis by virtue of the concise informational package of complex glycans and their relative distribution and densities, biospecific interactions between cells are rendered possible.
Abstract: Recent developments in the rapidly evolving field of glycobiology led to the notion of spatially and temporally regulated expression of glycan structures on the cell surface. By virtue of the concise informational package of complex glycans and their relative distribution and densities, biospecific interactions between cells are rendered possible. Thus, glycan expression is likely to have a major impact on morphogenesis during ontogenesis. This hypothesis has gained major support by recent work showing that mice in which the GnT-I gene (Mgat-I) was rendered nonfunctional displayed frequent inversions of the left-right asymmetry before exerting its effect as a lethal factor [94]. Moreover, a newly discovered inborn error of metabolism affecting GnT-II seems to be responsible for pronounced dysmorphic features [46].
33 citations
References
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15 Jan 2001
TL;DR: Molecular Cloning has served as the foundation of technical expertise in labs worldwide for 30 years as mentioned in this paper and has been so popular, or so influential, that no other manual has been more widely used and influential.
Abstract: Molecular Cloning has served as the foundation of technical expertise in labs worldwide for 30 years. No other manual has been so popular, or so influential. Molecular Cloning, Fourth Edition, by the celebrated founding author Joe Sambrook and new co-author, the distinguished HHMI investigator Michael Green, preserves the highly praised detail and clarity of previous editions and includes specific chapters and protocols commissioned for the book from expert practitioners at Yale, U Mass, Rockefeller University, Texas Tech, Cold Spring Harbor Laboratory, Washington University, and other leading institutions. The theoretical and historical underpinnings of techniques are prominent features of the presentation throughout, information that does much to help trouble-shoot experimental problems. For the fourth edition of this classic work, the content has been entirely recast to include nucleic-acid based methods selected as the most widely used and valuable in molecular and cellular biology laboratories. Core chapters from the third edition have been revised to feature current strategies and approaches to the preparation and cloning of nucleic acids, gene transfer, and expression analysis. They are augmented by 12 new chapters which show how DNA, RNA, and proteins should be prepared, evaluated, and manipulated, and how data generation and analysis can be handled. The new content includes methods for studying interactions between cellular components, such as microarrays, next-generation sequencing technologies, RNA interference, and epigenetic analysis using DNA methylation techniques and chromatin immunoprecipitation. To make sense of the wealth of data produced by these techniques, a bioinformatics chapter describes the use of analytical tools for comparing sequences of genes and proteins and identifying common expression patterns among sets of genes. Building on thirty years of trust, reliability, and authority, the fourth edition of Mol
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TL;DR: These findings either may reflect limitations in the methods of selection of hybridoma antibodies or point to important roles for the diverse carbohydrate structures as receptors for regulators of cell growth and differentiation.
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