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Evidence of calcium‐dependent pathway in the regulation of human β1,3‐glucuronosyltransferase‐1 (GlcAT‐I) gene expression: a key enzyme in proteoglycan synthesis
Author(s) -
Barré Lydia,
Venkatesan Narayanan,
Magdalou Jacques,
Netter Patrick,
Fournel-Gigleux Sylvie,
Ouzzine Mohamed
Publication year - 2006
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fj.05-5073fje
Subject(s) - ionomycin , chemistry , transcription factor , biochemistry , microbiology and biotechnology , gene , intracellular , biology
The importance of heparan‐ and chondroitin‐sulfate proteoglycans in physiological and pathological processes led to the investigation of the regulation of β1,3‐glucuronosyltransferase I (GlcAT‐I), responsible for the completion of glycosaminoglycanprotein linkage tetrasaccharide, a key step prior to polymerization of chondroitin‐ and heparan‐sulfate chains. We have cloned and functionally characterized GlcAT‐I 5′‐flanking regulatory region. Mutation analysis and electrophoretic mobility shift assays demonstrated the importance of Sp1 motif located at ‐65/‐56 position in promoter activity. Furthermore, we found that elevation of intracellular calcium concentration by the calcium ionophore ionomycin stimulated GlcAT‐I gene expression as well as glycosaminoglycan chain synthesis in HeLa cells. Bisanthracycline, an anti‐Sp1 compound, inhibited GlcAT‐I basal promoter activity and suppressed ionomycin induction, suggesting the importance of Sp1 in calcium induction of GlcAT‐I gene expression. Nuclear protein extracts from ionomycininduced cells exhibited an increased DNA binding of Sp1 factor to the consensus sequence at position −65/ −56. Signaling pathway analysis and MEK inhibition studies revealed the important role of p42/p44 MAPK in the stimulation of GlcAT‐I promoter activity by ionomycin. The present study identifies, for the first time, GlcAT‐I as a target of calcium‐dependent signaling pathway and evidences the critical role of Sp1 transcription factor in the activation of GlcAT‐I expression.—Barré, L., Venkatesan, N., Magdalou, J., Netter, P., Fournel‐Gigleux, S., Ouzzine, M. Evidence of calcium‐dependent pathway in the regulation of human β1,3‐glucuronosyltransferase (GlcAT‐I) gene expression: a key enzyme in proteoglycan synthesis. FASEB J. 20, E963‐E975 (2006)