Faculty / Research
Miguel Berrios, PhDProfessor Emeritus
Ph.D., Rockefeller University
Cell Structure and Function: The Cell Biology of DNA Damage and Repair
Eukaryotic cells segregate their genomic DNA to the nucleus, a compartment that is separated from the cytoplasm by a formidable yet permeable barrier, the nuclear envelope. Although the nuclear compartment provides the genome with a level of injury protection from environmental sources and reactive byproducts of metabolic processes occurring in the cytoplasm, it also provides cells with an opportunity for regulation. Thus, eukaryotic cells may be taking advantage of this functional compartmentalization as an effective strategy to contain DNA damage and regulate its repair.
Research in my laboratory focuses on oxidative DNA damage and repair and the impact that the cytoskeleton may have in regulating these processes. Our long-term goals are to determine how the DNA repair enzyme 8-oxoguanine DNA glycosylase (OGG1) may be regulating cytoskeletal function to maximize the cell’s capacity to repair the damage inflicted on DNA by reactive byproducts of its own metabolic activity. Although extensive information has been accumulated on the substrate specificity and the repair mechanism of the mammalian OGG1 protein, there is less information regarding the regulation of its distribution and activity in normally growing cells and in those experiencing oxidative stress. Recent evidence from our laboratory suggests that microtubules may be involved in the regulation of these processes.
There is accumulating evidence that microtubules may be involved in the regulation of DNA synthesis and repair. For instance, centrosomes, in addition to participating in the organization of microtubules and the spindle assembly, have been shown to play a critical role in cell cycle progression and in cellular responses to DNA replication defects and DNA damage. Tumor suppressor proteins, including adenomatous polyposis coli (APC), breast cancer-associated gene 1 (BRCA1) and P53, in addition to suppressing the early stages of malignancy, have also emerged as important microtubule modulators for their redistribution within cells. Our hypothesis is that cells use microtubules, in conjunction with associated proteins, to regulate the distribution and activity of OGG1, and as such, OGG1-microtubule binding emerges as an important cytoskeletal regulator. To test these hypotheses we are characterizing molecularly OGG1-microtubule binding and determining whether this binding plays a direct role in microtubule dynamics and the redistribution of OGG1. Once establishing the molecular components involved in OGG1-microtubule binding and how OGG1 binding affects microtubule dynamics we will investigate how microtubules, in conjunction with other elements of the cytoskeleton (and the karyoskeleton), regulate the distribution and in turn the activity of OGG1 and other base excision repair pathway components during normal and oxidative stress. To conduct these experiments we have chosen human, murine, Drosophila and yeast cells, the oxidative DNA lesion 8-oxoguanine and the base excision repair pathway enzymes OGG1, NEIL2 and DNA polymerase β as models.
Berrios, M. (1998). Isolation and Characterization of Nuclear Pore Complex-Lamina Fractions from Vertebrates. In: Methods in Cell Biology. M. Berrios, ed., Academic Press, New York. Vol 53, pp. 3-22.
Conlon, K.A., Rosenquist, T.A., and Berrios, M. (2002). Site-Directed Photochemical Disruption of the Actin Cytoskeleton by Actin-Binding Rose Bengal-Conjugates. J. Photochem. Photobiol. B, Biology 68:140-146.
Conlon, K.A., Zharkov, D.O, and Berrios, M. (2003). Immunofluorescent Localization of the Murine 8-Oxoguanine DNA Glycosylase (mOGGI) in Cells Growing Under Normal and Nutrient Deprivation Conditions. DNA Repair 2:1337-1352.
Conlon, K.A., Zharkov, D.O., and Berrios, M. (2004). Cell Cycle Regulation of the Murine 8-Oxoguanine DNA Glycosylase (mOGG1): mOGG1 Associates with Microtubules During Interphase and Mitosis. DNA Repair 3:1601-1615.
Conlon, K.A., Miller, H., Rosenquist, T.A., Zharkov, D.O., and Berrios, M. (2005). The Murine DNA Glycosylase NEIL2 (mNEIL2) and Human DNA Polymerase Beta Bind Microtubules In Situ and In Vitro. DNA Repair 4:419-431.
Kemeleva, E.A., Sinitsyna, O.I., Kolosova, N.G., Vasunina, E.A., Zharkov, D.O., Conlon, K.A., Berrios, M. and Nevinsky, G.A. (2006). Immunofluorescent detection of 8-oxoguanine DNA lesions in liver cells from aging OXYS rats, a strain prone to overproduction of free radicals. Mutat. Res. 599:88-97.
Conlon, K.A. and Berrios, M. (2007). Site-Directed Photoproteolysis of 8-Oxoguanine DNA Glycosylase 1 (OGG1) by Specific Porphyrin-Protein Probe Conjugates: A Strategy to Improve the Effectiveness of Photodynamic Therapy for Cancer. J. Photochem. Photobiol. B, Biology 87:9-17.
Berrios, M., Conlon, K.A., and Colflesh, D.E. (2010). Antifading Agents for Confocal Fluorescence Microscopy. In: Reliable Lab Solutions: Techniques in Confocal Microscopy. P.M. Conn, ed., Elsevier, New York. pp. 47-72.
Conlon, K. A., and Berrios, M. (2012). Photosensitized Reactions in Biology and Medicine. In: Trends in Photochemistry & Photobiology. Ninu, J. ed., Research Trends. Kerala, India. Vol 14, pp. 1-14.