Is the secret of VDAC Isoforms in their gene regulation? Characterization of human VDAC genes expression profile, promoter activity, and transcriptional regulators

• Published in: International journal of molecular sciences Vol. 21; no. 19; p. 7388
• Main Authors: Zinghirino, Federica, Pappalardo, Xena Giada, Messina, Angela, Guarino, Francesca, De Pinto, Vito
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 01-10-2020; MDPI
• Subjects: Alzheimer's disease; Animals; Apoptosis; Base Sequence; Binding Sites; Bioinformatics; Cell cycle; Cell differentiation; Cell Line, Tumor; Comparative analysis; Computational Biology - methods; core promoter; Databases, Genetic; E2F protein; Eukaryotes; expression profile; Gene expression; Gene Expression Profiling; Gene Expression Regulation; Gene regulation; gene structure; Genes; Genomes; HeLa Cells; Human tissues; Humans; Ion channels; Isoforms; Mammals; Membrane permeability; Mitochondria; mitochondrial function; Mitochondrial Proteins - genetics; Mitochondrial Proteins - metabolism; Motility; Multigene Family; Myc protein; Nucleotide Motifs; Observations; Permeability; Physiological aspects; Physiology; Pore formation; Pore-forming proteins; Promoter Regions, Genetic; Promoters; Protein Isoforms; Proteins; RNA polymerase; Sex determination; Sperm; Stem cells; Transcription activation; transcription factor binding sites; Transcription factors; Transcription Factors - metabolism; Transcriptional Activation; VDAC isoforms; Voltage-Dependent Anion Channels - genetics; Voltage-Dependent Anion Channels - metabolism; Italy; gene structure; mitochondrial function; transcription factor binding sites; core promoter; VDAC isoforms; expression profile
• ISSN: 1422-0067; 1661-6596; 1422-0067
• DOI: 10.3390/ijms21197388

VDACs (voltage-dependent anion-selective channels) are pore-forming proteins of the outer mitochondrial membrane, whose permeability is primarily due to VDACs' presence. In higher eukaryotes, three isoforms are raised during the evolution: they have the same exon-intron organization, and the proteins show the same channel-forming activity. We provide a comprehensive analysis of the three human
genes (
1-3), their expression profiles, promoter activity, and potential transcriptional regulators. VDAC isoforms are broadly but also specifically expressed in various human tissues at different levels, with a predominance of VDAC1 and VDAC2 over VDAC3. However, an RNA-seq cap analysis gene expression (CAGE) approach revealed a higher level of transcription activation of
gene. We experimentally confirmed this information by reporter assay of
promoter activity. Transcription factor binding sites (TFBSs) distribution in the promoters were investigated. The main regulators common to the three
genes were identified as E2F-myc activator/cell cycle (E2FF), Nuclear respiratory factor 1 (NRF1), Krueppel-like transcription factors (KLFS), E-box binding factors (EBOX) transcription factor family members. All of them are involved in cell cycle and growth, proliferation, differentiation, apoptosis, and metabolism. More transcription factors specific for each
gene isoform were identified, supporting the results in the literature, indicating a general role of VDAC1, as an actor of apoptosis for VDAC2, and the involvement in sex determination and development of VDAC3. For the first time, we propose a comparative analysis of human VDAC promoters to investigate their specific biological functions. Bioinformatics and experimental results confirm the essential role of the VDAC protein family in mitochondrial functionality. Moreover, insights about a specialized function and different regulation mechanisms arise for the three isoform gene.