Federica Zinghirino

Ciclo: XXXIII

Data inizio: 31/10/2017

Curriculum: Biomolecolari

Borsa: UniCT

Titolo tesi: Transcriptional regulation of human VDAC isoforms: analysis of their expression profile, promoter activity, and transcriptional regulators

Abstract: VDACs (Voltage Dependent Anion-selective Channels) are pore-forming proteins located in the outer mitochondrial membrane where they mediate metabolic exchanges between cytosol and mitochondria. In higher eukaryotes, VDACs form a multigene family that includes three isoforms (VDAC1-3) encoded by three different nuclear genes. Despite remarkably similar in sequence and structure, recent evidences suggest different biological roles in both normal and pathological conditions for each isoform. A crucial aspect of VDAC research is to understand how the expression of these three genes is regulated under normal conditions or in response to external stimuli. Clarifying this aspect could be essential to shed light on the specific functions of each isoform.

The aim of this PhD work was therefore to analyse the mechanism of transcriptional regulation of human VDAC genes. To this end, an analysis of VDAC expression profiles in different tissues was performed and the promoter structure and activity for each isoform was characterized.

RNA-seq transcriptome analysis revealed a ubiquitous distribution of VDAC transcripts across human tissues, with VDAC1 and VDAC2 predominating over VDAC3. However, RNA-seq CAGE data obtained from the FANTOM5 project reported that the most highly expressed isoform is VDAC3, probably due to the higher transcriptional activity of its gene promoter. Indeed, both the RT-PCR results and the promoter activity assay confirmed that, although VDAC1 is the most abundant isoform, the VDAC3 gene promoter has a higher transcriptional activity. In addition, bioinformatic analysis of the VDAC promoters revealed the presence of binding sites for transcription factors involved in the regulation of cell proliferation, differentiation, apoptosis, and metabolism. A unique set of transcription factors was also defined for each isoform, highlighting their possible involvement in specific cellular processes. Finally, the regulatory mechanism of VDAC1 during metabolic stress induced by nutrient deprivation and hypoxia was studied. In this context of metabolic

adaptation, the expression of VDAC1 and its promoter activity were significantly increased. We have also shown that NRF-1 and HIF-1α factors contribute to the modulation of VDAC1 promoter activity under these stress conditions.

Tutor: Guarino

Data Conseguimento Titolo:

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Email: fedezingh@hotmail.it

Periodi all'estero- Sede e data: Si

Esperienze post-Dottorato ed attuale occupazione: Research Fellow (dal 17/01/2022) presso UCL Great Ormond Street Institute of Child Health (UCL GOS ICH) (London, UK)