G-Quadruplex Modulation of SP1 Functional Binding Sites at the KIT Proximal Promoter |
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| Authors: | Silvia Da Ros Giulia Nicoletto Riccardo Rigo Silvia Ceschi Eleonora Zorzan Mauro Dacasto Mery Giantin Claudia Sissi |
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| Affiliation: | 1.Department of Pharmaceutical and Pharmacological Sciences, University of Padua, 35131 Padua, Italy; (S.D.R.); (G.N.); (R.R.); (S.C.);2.Department of Comparative Biomedicine and Food Science, University of Padua, 35020 Legnaro, Italy; (E.Z.); (M.D.);3.CRIBI Biotechnology Center (Centro di Ricerca Interdipartimentale per le Biotecnologie Innovative), University of Padua, 35131 Padua, Italy |
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| Abstract: | The regulation of conformational arrangements of gene promoters is a physiological mechanism that has been associated with the fine control of gene expression. Indeed, it can drive the time and the location for the selective recruitment of proteins of the transcriptional machinery. Here, we address this issue at the KIT proximal promoter where three G-quadruplex forming sites are present (kit1, kit2 and kit*). On this model, we focused on the interplay between G-quadruplex (G4) formation and SP1 recruitment. By site directed mutagenesis, we prepared a library of plasmids containing mutated sequences of the WT KIT promoter that systematically exploited different G4 formation attitudes and SP1 binding properties. Our transfection data showed that the three different G4 sites of the KIT promoter impact on SP1 binding and protein expression at different levels. Notably, kit2 and kit* structural features represent an on-off system for KIT expression through the recruitment of transcription factors. The use of two G4 binders further helps to address kit2-kit* as a reliable target for pharmacological intervention. |
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| Keywords: | G-quadruplex KIT promoter SP1 gene expression |
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