Characterization of P1 promoter activity of the β-galactoside α2,6-sialyltransferase I gene (siat 1) in cervical and hepatic cancer.
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Date
2012-06
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Abstract
The level of β-galactoside α2,6-sialyltransferase I (ST6Gal I) mRNA, encoded by the gene siat1, is increased in
malignant tissues. Expression is regulated by different promoters – P1, P2 and P3 – generating three mRNA isoforms
H, X and YZ. In cervical cancer tissue the mRNA isoform H, which results from P1 promoter activity, is increased. To
study the regulation of P1 promoter, different constructs from P1 promoter were evaluated by luciferase assays in
cervical and hepatic cell lines. Deletion of a fragment of 1048 bp (−89 to +24 bp) increased 5- and 3-fold the promoter
activity in C33A and HepG2 cell lines, respectively. The minimal region with promoter activity was a 37 bp fragment
in C33A cells. The activity of this region does not require the presence of an initiator sequence. In HepG2 cells the
minimal promoter activity was detected in the 66 bp fragment. Sp1 (−32) mutation increased the promoter activity
only in HepG2 cells. HNF1 mutation decreased promoter activity in HepG2 cell line but not in C33A cells. We
identified a large region that plays a negative regulation role. The regulation of promoter activity is cell type specific.
Our study provides new insights into the complex transcriptional regulation of siat1 gene.
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Keywords
Cancer cells, β-galactoside α2,6-sialyltransferase I, promoter, siat 1 gene
Citation
Milflores-Flores Lorena, MillÃn-Perez Lourdes, Santos-Lopez Gerardo, Reyes-Leyva Julio, Vallejo-Ruiz Veronica. Characterization of P1 promoter activity of the β-galactoside α2,6-sialyltransferase I gene (siat 1) in cervical and hepatic cancer. Journal of Biosciences. 2012 Jun; 37 (2): 259-269.