Coordinate expression of beta-galactoside alpha 2,6-sialyltransferase mRNA and enzyme activity in suckling rat jejunum cultured in different media: transcriptional induction by dexamethasone.
In attempting to elucidate the molecular basis of the expression of alpha 2,6-sialyltransferase (alpha 2,6-ST) in jejunal explants of 7-day-old rats during cultivation, the total jejunal RNA was analysed by hybridization using a cDNA clone encoding rat liver alpha 2,6-ST. Under cultivation in both serum-free and serum-containing media jejunal alpha 2,6-ST mRNA closely paralleled the bound (100,000 g pellet) as well as the soluble (100,000 g supernatant) alpha 2,6-ST activity, the correlation coefficients being 0.976 and 0.816, respectively. Dexamethasone (Dx) treatment enhanced alpha 2,6-ST mRNA and membrane-bound alpha 2,6-ST activity in close correlation. Jejunal alpha 2,6-ST mRNA is sensitive to actinomycin D and is lost with apparently identical kinetics in Dx-stimulated and control explants, suggesting that regulation by Dx may be exerted by altering the rate of mRNA synthesis. Dx-dependent activation resulted in elevation of the 4.3-Kb mRNA and can be inhibited by the antiglucocorticoid onapristone, demonstrating the participation of the glucocorticoid receptor pathway.
Kolínská
J
J
Institute of Physiology, Czech Academy of Sciences, Prague, Czech Republic.
Zákostelecká
M
M
Hamr
A
A
Baudysová
M
M
D000818:Animals; D002478:Cells, Cultured; D003470:Culture Media; D003907:Dexamethasone / Q000494:pharmacology*; D004790:Enzyme Induction / Q000187:drug effects; D015971:Gene Expression Regulation, Enzymologic; D005938:Glucocorticoids / Q000494:pharmacology*; D007583:Jejunum / Q000201:enzymology*; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics; D051381:Rats; D017208:Rats, Wistar; D012799:Sialyltransferases / Q000096:biosynthesis* / Q000235:genetics; D015533:Transcriptional Activation / Q000187:drug effects*; D000094802:beta-D-Galactoside alpha 2-6-Sialyltransferase
D003470:Culture Media; D005938:Glucocorticoids; D012333:RNA, Messenger; D003907:Dexamethasone; D012799:Sialyltransferases; D000094802:beta-D-Galactoside alpha 2-6-Sialyltransferase