Infectious Disease; Microbiology; Molecular and Cellular Biology; Molecular genetics; DNA Replication, Recombination and Repair; Virology; Genome Integrity
The major focus of my laboratory is in understanding the molecular machines that make up the DNA replication forks of the small human DNA viruses, polyoma- and papillomaviruses. Papillomaviruses and polyomaviruses are human pathogens; human papillomavirus (HPV) results in a vast number of human cancers, and the human polyomaviruses JC and BK cause serious disease and death in immunocompromised patients. Both viral systems provide important models for the study of human DNA replication mechanisms and have allowed for vital insights into eukaryotic DNA replication. The study of polyomavirus DNA replication led to the first identification of many cellular DNA replication complexes and processes; papillomavirus has provided the best structures and models to date of replicative hexameric DNA helicases and how they function. I typically train undergraduate, master’s and doctoral students and postdoctoral scholars, assistant research professors and laboratory technicians. My laboratory focuses on two primary areas. One is elucidating the dynamic protein-protein interactions that allow the series of enzymes required to replicate DNA to act in concert and in the correct sequence required to duplicate the genome. My laboratory has been at the forefront of identifying the interactions between the one critical HPV DNA replication protein, the origin-binding DNA helicase, E1, and cellular DNA replication proteins. Understanding these interactions and the roles they play in the HPV DNA replication process has helped our understanding of, and continues to lead to information that tells us more about how both viral and eukaryotic DNA replication forks function. In addition, as we identify protein-protein interactions between HPV E1 and cellular factors that are essential for HPV DNA synthesis, we will uncover potential targets for development of broad-range HPV antivirals that could act to block HPV replication. We recently obtained a large multilaboratory NIH research grant to investigate just this possibility for the interaction between HPV E1 and the human DNA replication protein, Topoisomerase I. The second primary area of investigation is elucidating how the cellular DNA damage response (DDR) pathways inhibit DNA replication when cells are subjected to DNA damage. For many years, the DDR field focused on the effects of DDR on the cell cycle kinases as the only method by which DNA replication was arrested. In the mid- to late-2000s, researchers recognized that in mammalian cells there is also a substantial (tenfold) inhibition of elongation of DNA replication following DDR. The mechanisms for this inhibition are unknown. Using both in vitro and cell-based simian virus 40 (SV40) DNA replication systems, we have shown that SV40 DNA replication is also shut down in response to DDR kinase pathways and that this is not based on cell cycle kinase action. Therefore, SV40 provides a useful model system for determining how elongation of DNA replication is inhibited by DDR. Furthermore, we have shown that in contrast HPV DNA replication does not respond to DDR, providing us an important control DNA replication system for these studies. (The lack of DDR arrest of HPV DNA replication likely explains why HPV integrates so readily into host cell chromosomes−an important step for HPV-induced carcinogenesis). Our studies on the DDR effect on polyoma and papilloma virus DNA replication will lead to insights into the effect of DDR on cellular DNA replication as well as an understanding of how HPV integrates into host cell chromosomes causing HPV-induced cancers.
Bioinformatics; Cell growth, differentiation and development; Gene Expression; Gene therapy; Genome Integrity; Genomics and proteomics; Molecular Basis of Disease; Molecular and Cellular Biology; Neurobiology; Signal Transduction; Stem Cells; Transcription and Translation
The long term mission of our laboratory, which I co-direct with Dr. Ewa Stachowiak, is to understand the principles governing molecular control of neural development, the implications for developmental- and aging-related diseases and the wide ranging effects on brain functions including behavior. The main achievement of our program has been the discovery of “Integrative Nuclear FGFR1 Signaling”, INFS a universal signaling mechanism which plays a novel integral role in cell development and complements other universal mechanisms such as mitotic cycle and pluripotency .Based on these revolutionary findings we have formulated a new theory called “Feed-Forward End-Gate Signaling” that explains how epigenetic factors either extracellular like neurotransmitters, hormonal or growth factors or intracellular signaling pathways control developmental gene programs and cellular development. This discovery is a product of our twenty-year multidisciplinary research that has been reported in several peer-reviewed papers in major journals including Proc. Natl. Acad. of Science (USA), Integrative Biology, Molecular Biology of the Cell, Journal of Cell Biology, Journal of Biological Chemistry, Journal of Physical Chemistry (etc.). In addition, we have applied this theory to analyze the etiology of neurodevelopmental /neurodegenerative disorders, and cancer in order to utilize it in new potential therapies. Towards these goals we have employed new technologies for an in vivo gene transfer, developed new transgenic mouse models for Schizophrenia and Parkinson-like diseases and established an interdisciplinary Molecular and Structural Neurobiology and Gene Therapy Program which has o engaged researchers from the different UB departments, other universities in the US as well as foreign institutions including Hannover Medical School (Germany), Gdansk Medical University, and Polish Academy of Science. Detailed research activities and future goals of our research program: 1. Molecular mechanisms controlling development of neural stem and related cells. In studying molecular mechanisms controlling development of neural stem and related cells we have established a novel universal signal transduction mechanism -Feed-Forward-And Gate network module that effects the differentiation of stem cells and neural progenitor cells. In the center of this module is the new gene-controlling mechanism "Integrative Nuclear Fibroblast Growth Factor Receptor-1 (FGFR1) Signaling" (INFS), which integrates diverse epigenetic signals and controls cell progression through ontogenic stages of proliferation, growth, and differentiation. We have shown that, Fibroblast Growth Factor Receptor-1 (FGFR1) a protein previously thought to be exclusively involved with transmembrane FGF signaling, resides in multiple subcellular compartments and is a multifactorial molecule that interacts with diverse cellular proteins In INFS, newly synthesized FGFR1 is released from the endoplasmic reticulum and translocates to the nucleus. In the nucleus, FGFR1 associates with nuclear matrix-attached centers of RNA transcription, interacts directly with transcriptional coactivators and kinases, activates transcription machinery and stimulates chromatin remodeling conducive of elevated gene activities. Our biophotonic experiments revealed that the gene activation by nuclear FGFR1 involves conversion of the immobile matrix-bound and the fast kinetic nucleoplasmic R1 into a slow kinetic chromatin binding population This conversion occurs through FGFR1’s interaction with the CBP and other nuclear proteins. The studies support a novel general mechanism in which gene activation is governed by FGFR1 protein movement and collisions with other proteins and nuclear structures. The INFS governs expression of developmentally regulated genes and plays a key role in the transition of proliferating neural stem cells into differentiating neurons development of glial cells, and can force neoplastic medulloblastoma and neuroblastoma cells to exit the cell cycle and enter a differentiation pathway and thus provides a new target for anti-cancer therapies. In our in vitro studies we are using different types of stem cells cultures, protein biochemistry, biophotonics analyses of protein mobility and interactions [Fluorescence Recovery after Photobleaching (FRAP), Fluorescence Loss In Photobleaching (FLIP), and Fluorescence Resonance Energy Transfer (FRET)] and diverse transcription systems to further elucidate the molecular circuits that control neural development. 2. Analyses of neural stem cell developmental mechanisms in vivo by direct gene transfer into the mammalian nervous system. An understanding of the mechanisms that control the transition of neural stem/progenitor cells (NS/PC) into functional neurons could potentially be used to recruit endogenously-produced NS/PC for neuronal replacement in a variety of neurological diseases. Using DNA-silica based nanoplexes and viral vectors we have shown that neuronogenesis can be effectively reinstated in the adult brain by genes engineered to target the Integrative Nuclear FGF Receptor-1 Signaling (INFS) pathway. Thus, targeting the INFS in brain stem cells via gene transfers or pharmacological activation may be used to induce selective neuronal differentiation, providing potentially revolutionizing treatment strategies of a broad range of neurological disorders. 3. Studies of brain development and neurodevelopmental diseases using transgenic mouse models. Our laboratory is also interested in the abnormal brain development affecting dopamine and other neurotransmitter neurons and its link to psychiatric diseases, including schizophrenia. Changes in FGF and its receptors FGFR1 have been found in the brains of schizophrenia and bipolar patients suggesting that impaired FGF signaling could underlie abnormal brain development and function associated with these disorders. Furthermore the INFS mechanism, integrates several pathways in which the schizophrenia-linked mutations have been reported. To test this hypothesis we engineered a new transgenic mouse model which results from hypoplastic development of DA neurons induced by a tyrosine kinase-deleted dominant negative mutant FGFR1(TK-) expressed in dopamine neurons. The structure and function of the brain’s DA neurons, serotonin neurons and other neuronal systems including cortical and hippocampal neurons are altered in TK- mice in a manner similar to that reported in patients with schizophrenia. Moreover, TK- mice express behavioral deficits that model schizophrenia-like positive symptoms (impaired sensory gaiting), negative symptoms (e.g. low social motivation), and impaired cognition ameliorated by typical or atypical antipsychotics. Supported by the grants from the pharmaceutical industry we are investigating new potential targets for anti-psychotic therapies using our preclinical FGFR1(TK-) transgenic model. Our future goals include in vivo gene therapy to verify whether neurodevelopmental pathologies may be reversed by targeting endogenous brain stem cells. Together with the other researchers of the SUNY Buffalo we have established Western New York Stem Cells Analysis Center in 2010 which includes Stem Cell Grafting and in vivo Analysis core which I direct. Together with Dr. E. Tzanakakis (UB Bioengineering Department) we have written book “ Stem cells- From Mechanisms to Technologies’ (World Scientific Publishing, 2011). Educational Activities and Teaching: I have participated together with the members of our neuroscience community in developing a new Graduate Program in Neuroscience at the SUNY, Buffalo. I am teaching neuroanatomy courses for dental students (ANA811) and for graduate students (NRS524). At present I participate in team-taught graduate courses in Neuroscience and Developmental Neuroscience (NRS 520, 521 and NRS 524). I am serving as a mentor for several undergraduate, graduate (masters and doctoral students) and postdoctoral fellows in the Neuroscience Program, Anatomy and Cell Biology Program and in the IGERT program in the Departments of Chemistry and Engineering. Additionally to mentoring master and Ph.D. students at the UB, I have helped to train graduate students in the University of Camerino (Italy) and Hannover Medical School (Germany). The works of our graduate students have been described in several publications.
DNA Replication, Recombination and Repair; Genome Integrity; Molecular and Cellular Biology; Molecular genetics; Protein Function and Structure
In my laboratory, we are interested in the general problem of maintaining genome stability. To this end, we focus on two distinct aspects of genome stability: 1) the roles of mismatch (MMR) proteins in multiple pathways for DNA repair and 2) the manner in which regulation of dNTP pools, through the regulation of ribonucleotide reductase (RNR) activity, impacts genome integrity. 1) MMR proteins recognize many different types of DNA lesions and then target the lesion for the appropriate repair pathway. We are interested in the mechanism(s) by which recognition of a lesion is translated into the appropriate DNA repair pathway, using the yeast Saccharomyces cerevisiae as a model system. Is it through differential protein-nucleic acid or protein-protein interactions? To address these questions as well as the regulation of DNA repair pathway selection, we use a combination of genetic, biochemical and biophysical approaches. 2) RNR activity modulates the level of dNTPs that are available in a cell at a given time. Higher levels of dNTPs lead to higher mutation rates. We are interested in the various ways in which misregulated dNTP pools might affect cellular metabolism and affect the stability of the genome.
DNA Replication, Recombination and Repair; Gene Expression; Genome Integrity; Microbiology; Molecular and Cellular Biology; Protein Function and Structure; Signal Transduction
We are interested in developing an integrated mechanistic view of how organisms coordinate the actions of their DNA replication machinery with those of other cellular factors involved in DNA repair and damage tolerance. Failure to properly coordinate these functions leads to mutations, genome instability, and in extreme cases, cell death. We utilize a combination of biochemical, biophysical, and genetic approaches to investigate the molecular mechanisms of DNA replication, DNA repair, and error-prone DNA damage tolerance functions in Escherichia coli. The primary mechanism for damage tolerance involves direct bypass of damaged bases in the DNA. This process is inherently error-prone, and is the basis for most mutations. Current efforts are focused on understanding the mechanisms by which the actions of high fidelity and error-prone lesion bypass DNA polymerases are coordinated with each other, as well as other proteins involved in DNA metabolism. Our goal in this work is to develop methods that enable us to control the fidelity of DNA repair for therapeutic gain. We are also interested in understanding the mechanisms that contribute to DNA mutagenesis in the opportunistic human pathogen, P. aeruginosa. P. aeruginosa is a particular problem for individuals afflicted with cystic fibrosis. Persistent colonization of cystic fibrosis airways with P. aeruginosa serves as a major source of morbidity and mortality for these patients. The ability of P. aeruginosa to persist in the airways relies in part on its ability to adapt to the continuously changing environment within the diseased airways. We are particularly interested in determining the contribution of mutagenesis and DNA repair to adaptive mutations that contribute to clonal expansion and pathoadaptation of P. aeruginosa during colonization of cystic fibrosis airways.