Differentiation -dependent expression of human beta-galactoside alpha 2,6-sialyltransferase mRNA in colon carcinoma CaCo-2 cells.
We have previously documented a dramatic elevation in the activity of alpha 2,6-sialytransferase towards Gal beta 1,4GlcNAc (EC 2.4.99.1) (alpha 2,6ST) in CaCo-2 cells maintained in culture for several days after confluence to elicit a high degree of enterocytic differentiation phenotype. Northern analysis performed with a probe complementary to a region of human alpha 2,6ST mRNA common to all known transcripts demonstrated that the expression of alpha 2,6ST mRNA in CaCo-2 cells increased with the degree with the degree of differentiation. When probes complementary to 5'-untranslated exons (Y + Z or X) previously identified in transcripts isolated from human placenta and from several human lymphoblastoid cell lines were used, no hybridization signal with mRNA of CaCo-2 cells was found, as reported for the mRNA of hepatoma cell line HepG2 (Wang XC, Vertino A, Eddy RL, Byers MG, Jani-Sait SN, Shows TB, Lau JTY (1993) J Biol Chem 268: 4355-61). These results support the notion that the major alpha 2,6ST transcript of CaCo-2 cells was the hepatoma isoform or a new one, so far unreported. Consistent with the differentiation-dependent increase in alpha 2,6ST-mRNA expression, an elevation of the reactivity with Sambucus nigra agglutinin of differentiated CaCo-2 cell-surface was observed, indicating an enhanced alpha 2,6-sialylation of membrane glycoconjugates.
Dall'Olio
F
F
Department of Experimental Pathology, University of Bologna, Italy.
Malagolini
N
N
Guerrini
S
S
Lau
J T
JT
Serafini-Cessi
F
F
D001483:Base Sequence; D018938:Caco-2 Cells / Q000201:enzymology*; D002240:Carbohydrate Sequence; D002454:Cell Differentiation; D017931:DNA Primers / Q000235:genetics; D015870:Gene Expression; D006001:Glycoconjugates / Q000737:chemistry / Q000378:metabolism; D006801:Humans; D007700:Kinetics; D008969:Molecular Sequence Data; D009844:Oligosaccharides / Q000737:chemistry / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics* / Q000378:metabolism*; D012799:Sialyltransferases / Q000235:genetics* / Q000378:metabolism; D013379:Substrate Specificity; D000094802:beta-D-Galactoside alpha 2-6-Sialyltransferase
D017931:DNA Primers; D006001:Glycoconjugates; D009844:Oligosaccharides; D012333:RNA, Messenger; D012799:Sialyltransferases; D000094802:beta-D-Galactoside alpha 2-6-Sialyltransferase