Vera Bianchi
Vera Bianchi
affiliation: Università di Padova
research area(s): Cell Biology, Molecular Biology
Course: Biosciences and Biotechnologies
University/Istitution: Università di Padova
Born in Verona, Italy, October 23, 1946

Positions held at the University of Padova:

1990/- Full Professor of Cell Biology, Faculty of Sciences
1983/1990 Associate Professor of Cell Biology, Faculty of Sciences
1973/1983 Assistant professor of General Biology, Faculty of Sciences and Medical School
1972/1973 research fellow (Institute of Animal Biology)

Research fellowships:

Short term fellowships from EMBO (1987 and 1991) and UICC (1993 and 1999).
Long term research fellowship from the European Science Foundation (1984 and 1985), Karolinska Institute, Stockholm, Sweden

Education and training:

1971: “Laurea” in Biology magna cum laude from the University of Padova.
1969: “Laurea” in Natural Sciences magna cum laude from the University of Padova
1965: High School exam from Liceo Classico Scipione Maffei, Verona

The laurea dissertations dealt with muscle cell differentiation in primary cultures of myoblasts and the formation of hybrid muscle fibers in co-cultures of myoblasts from chicken embryos and newborn rats.

On different occasions she has been visiting scientist or visiting professor at the Karolinska Institute (Departments of Biochemistry and of Cell and Molecular Biology), at the University of Stockholm (Department of Genetics) and at the Department of Biochemistry of Stanford University.
VB started working with mammalian cells in culture in the late 1960s when she preparing her thesis on the formation of inter-specific hybrid fibers in primary cultures of skeletal muscle cells. She later studied several aspects of chemical cytotoxicity and mutagenicity, with emphasis on DNA metabolism and DNA repair. Since the mid-1980s her main interest has been in the field of deoxyribonucleotide metabolism in mammalian cells, more recently focused on the origin and regulation of mitochondrial DNA precursors. Her expertise is in cellular biochemistry and molecular cell biology. Main recent accomplishments: 1. demonstration of the regulatory role of substrate cycles between deoxynucleosides and their monophosphates for DNA replication in mammalian cells; 2. demonstration that such cycles can be exploited to potentiate the uptake and efficacy of nucleoside analogs of therapeutic interest; 3. demonstration, based on the molecular analysis of mutations at the hprt locus, that dGTP accumulation is more mutagenic than dTTP in cells with imbalanced dNTP pools; 4. demonstration, in CEM lymphoblasts synchronized by centrifugal elutriation, that exogenous deoxycytidine is freely incorporated into replicating DNA, with no special "channelling" mechanism excluding it from the pool used by DNA polymerases; 5. cloning of fpr, the gene coding for the E.coli flavodoxin (ferredoxin) reductase, an enzyme involved in the activation of the anaerobic ribonucleotide reductase and in the oxidative stress response; 6. production of knock-out mutants for fpr by homologous recombination, and demonstration that such mutants exhibit increased sensitivity of oxidative damage; 7. cloning of the mammalian cytosolic 5' (3')-deoxyribonucleotidase (cdN) and demonstration that it is involved in the turnover of pyrimidine deoxyribonucleotide pools; 8. discovery of a new human deoxyribonucleotidase (mdN) and demonstration that it is a mitochondrial enzyme regulating thymidine phosphorylation within mitochondria; 9. development of a novel procedure for the study of mitochondrial deoxyribonucleotide pools and their dynamics in mammalian cells; 10. molecular and biochemical characterization of cellular models of mitochondrial neurogastroencephalo-myopathy (MNGIE) and thymidine kinase 2 deficiency, revealing how the interplay of degradative and anabolic enzymes regulates the mitochondrial dTTP pool in quiescent cells; 10. Demonstration that the same close metabolic connection exists between mitochondrial and cytosolic dGTP pools; 11. p53R2-dependent de novo synthesis occurs during quiescence, although at a ~50-fold lower level than in cycling cells, and is necessary to support both mtDNA synthesis and nuclear DNA repair; 12. Analysis of dNTP metabolism in an in vitro model of myogenesis and demonstration that silencing of either thymidine kinase 2 or deoxyguanosine kinase decreases all four dNTP pools, possibly by interfereing with the allosteric regulation of p53R2-dependent ribonucleotide reduction.

The results have been presented in seminars and invited lectures in Italy, Sweden, the Netherlands and the U.S. and to National and International meetings.
Selected recent publications:

1. Franzolin E, Rampazzo C, Perez-Perez MJ, Hernandez AI, Balzarini J, Bianchi V. (2006) Bromovinyl-deoxyuridine: A selective substrate for mitochondrial thymidine kinase in cell extracts. Biochem Biophys Res Commun. 344 (1):30-36.
2. Pontarin G, Ferraro P, Valentino ML, Hirano M, Reichard P, Bianchi V. (2006) Mitochondrial DNA depletion and thymidine phosphate pool dynamics in a cellular model of mitochondrial neurogastrointestinal encephalomyopathy. J Biol Chem. 281:22720-8.
3. Ferraro P, Nicolosi L, Bernardi P, Reichard P, Bianchi V. (2006) Mitochondrial deoxynucleotide pool sizes in mouse liver and evidence for a transport mechanism for thymidine monophosphate. Proc Natl Acad Sci U S A. 103:18586-91.
4. Pontarin G, Ferraro P, Hakansson P, Thelander L, Reichard P, Bianchi V. (2007) p53R2-dependent ribonucleotide reduction provides deoxyribonucleotides in quiescent human fibroblasts in the absence of induced DNA damage. J Biol Chem., 282:16820-16828.
5. Wallden K, Stenmark P, Nyman T, Flodin S, Graslund S, Loppnau P, Bianchi V, Nordlund P. (2007) Crystal structure of human cytosolic 5'-nucleotidase II: insights into allosteric regulation and substrate recognition. J Biol Chem. 282:17828-36.
6. Rampazzo C, Fabris S, Franzolin E, Crovatto K, Frangini M, Bianchi V. (2007) Mitochondrial thymidine kinase and the enzymatic network regulating thymidine triphosphate pools in cultured human cells J Biol Chem, 282:34758-69.
7. K. Walldén, A. Rinaldo-Matthis, B. Ruzzenente, C. Rampazzo, V. Bianchi and P. Nordlund (2007)
Crystal structures of human and murine deoxyribonucleotidases: insights into recognition of substrates and nucleotide analogues. Biochemistry 46:13809-18.
8. Pontarin G, Fijolek A, Pizzo P, Ferraro P, Rampazzo C, Pozzan T, Thelander L, Reichard PA, Bianchi V. (2008) Ribonucleotide reduction is a cytosolic process in mammalian cells independently of DNA damage Proc Natl Acad Sci U S A. 105:17801-6
9. Leanza L, Ferraro P, Reichard P, Bianchi V. (2008) Metabolic interrelations within guanine deoxynucleotide pools for mitochondrial and nuclear DNA maintenance. J Biol Chem. 283:16437-45.
10. Frangini M, Rampazzo C, Franzolin E, Lara MC, Vilà MR, Martí R, Bianchi V. (2009) Unchanged thymidine triphosphate pools and thymidine metabolism in two lines of thymidine kinase 2-mutated fibroblasts. FEBS J. 276: 1104-13.
11. Ferraro, P., Franzolin, E., Pontarin, G., Reichard, P., and Bianchi, V. (2010) Quantitation of cellular deoxynucleoside triphosphates Nucleic Acids Res. 38, e 85
12. Leanza L, Miazzi C, Ferraro P, Reichard P, Bianchi V, (2010) Activation of guanine-β-d-arabinofuranoside and deoxyguanosine to triphosphates by a common pathway blocks T lymphoblasts at different checkpoints Exp Cell Res. 316:3443-53
13. Rampazzo C, Miazzi C, Franzolin E, Pontarin G, Ferraro P, Frangini M, Reichard P, Bianchi V. (2010) Regulation by degradation, a cellular defense against deoxyribonucleotide pool imbalances. Mutat Res. 703:2-10
14. Pontarin G, Ferraro P, Rampazzo C, Kollberg G, Holme E, Reichard P, Bianchi V. (2011) Deoxyribonucleotide metabolism in cycling and resting human fibroblasts with a missense mutation in p53R2, a subunit of ribonucleotide reductase J Biol Chem. 286: 11132-40.
15. Franzolin E, Miazzi C, Frangini M, Palumbo E, Rampazzo C, Bianchi V. (2012) The pyrimidine nucleotide carrier PNC1 and mitochondrial trafficking of thymidine phosphates in cultured human cells. Exp Cell Res. 318: 2226-36
16. Pontarin G, Ferraro P, Bee L, Reichard P, Bianchi V. (2012) Mammalian ribonucleotide reductase subunit p53R2 is required for mitochondrial DNA replication and DNA repair in quiescent cells. Proc Natl Acad Sci U S A. 109:13302-7.
17. Pontarin G, Ferraro P, Reichard P, Bianchi V (2012) Out of S phase: shift of subunits for ribonucleotide reduction Cell Cycle 11: 4099-4100.
18. Frangini M, Franzolin E, Chemello F, Laveder P, Romualdi C, Bianchi V, Rampazzo C (2013) Synthesis of mitochondrial DNA precursors during myogenesis, an analysis in purified C2C12 myotubes. J Biol Chem. First Published on January 7, 2013, doi:10.1074/jbc.M112.441147
No projects are available to students for the current accademic year.