FisMat2017 - Submission - View

Abstract's title: A complete UV Resonant Raman scattering characterization of deoxycytidine triphosphate: towards the best experimental conditions to detect DNA cytosine methylation
Submitting author: Francesco D'Amico
Affiliation: Elettra Sinctrotrone Trieste S.C.pA.
Affiliation Address: Strada Statale 14 - km 163,5 in AREA Science Park 34149 Basovizza, Trieste ITALY
Country: Italy
Oral presentation/Poster (Author's request): Oral presentation
Other authors and affiliations: Francesco D’Amico (IUVS beamline, Elettra Sinctrotrone Trieste S.C.pA., Basovizza, Trieste, 34149 Italy) Paolo Zucchiatti (Dipartimento di Fisica, Università degli Studi di Trieste, Via A. Valerio 2, 34100 Trieste, SISSI beamline, Elettra Sinctrotrone Trieste S.C.pA., Basovizza, Trieste, 34149 Italy, Plasmon Nanotechnologies line, IIT, Via Morego 30, Genova, 16163 Italy) Nicola Cefarnin (SISSI beamline, Elettra Sinctrotrone Trieste S.C.pA., Basovizza, Trieste, 34149 Italy) Lisa Vaccari (SISSI beamline, Elettra Sinctrotrone Trieste S.C.pA., Basovizza, Trieste, 34149 Italy) Barbara Rossi (IUVS beamline, Elettra Sinctrotrone Trieste S.C.pA., Basovizza, Trieste, 34149 Italy) Cettina Bottari (IUVS beamline, Elettra Sinctrotrone Trieste S.C.pA., Basovizza, Trieste, 34149 Italy, Dipartimento di Fisica, Università degli Studi di Trieste, Via A. Valerio 2, 34100 Trieste) Alessandro Gessini (IUVS beamline, Elettra Sinctrotrone Trieste S.C.pA., Basovizza, Trieste, 34149 Italy) Claudio Masciovecchio (IUVS beamline, Elettra Sinctrotrone Trieste S.C.pA., Basovizza, Trieste, 34149 Italy)
Abstract

Methylation of DNA is a heritable, enzyme-induced modification to DNA structure without alteration of the specific sequence of the base pairs responsible for encoding the genome. This epigenetic modification plays an essential role in normal biologic processes, but distinct and abnormal patterns of methylation are observed in many forms of cancers [1-3]. DNA methylation occurs at the 5’ position of the pyridine ring of the cytosine residues within CpG sites, that are regions of DNA where a cytosine nucleotide is followed by a guanine nucleotide in the linear sequence of basis along its 5’à3’ direction. The frequency of CpG dinucleotides are statistically underrepresented in vertebrate genomes, but they are present with a high frequency in particular regions of the genome called CpG islands. These regions typically occur at or near the transcription site of genes, usually housekeeper genes including known tumor suppressor genes, in their promoter regions. Methylation of these promoter regions results in the subsequent failure to express their functional proteins. Consequently, alteration of DNA methylation may represent an early and fundamental step in the pathway by which normal tissue undergoes neoplastic transformation [4]. Raman spectroscopy has been used in the past to characterize the chemical structure of DNA by using UV excitation instead of visible one, allowing to obtain a higher scattering efficiency without intense fluorescence backgrounds [5]. Futheremore, thanks to the resonance conditions, by exciting the UV Raman spectra of DNA with specific wavelengths it is possible to selectively enhance the vibrational modes associated to specific nitrogenous basis.  A clear and unique identification of DNA methylation trough UVRR pass through a complete spectral characterization of DNA cytosine, pristine and methylated. It must be performed by using several excitation wavelengths with the aim to find the best experimental conditions where methylation can be identified. In this contribution we will show a complete UVRR spectral characterization of deoxycytidine triphosphateas a function of excitation wavelength and temperature. The vibrational spectral indentification and the resonance effects detected have been described  by quantum mechanics calculations.

[1]        A. Razin and A. Riggs, Cell (1980), 210.

[2]        D. Sutter and W. Doerfler, Proc Natl Acad Sci U S A. (1980), 77.

[3]        van der Ploeg and Flavell, Cell (1980), 19.

[4]        A. Wajed and R. DeMeester, Ann Surg. (2001), 234.

[5]        F. D’Amico, and C. Masciovecchio, Nucl. Instrum. Methods Phys. Res., Sect. A. (2013), 703.