Research in the McCulloch laboratory focuses on the role of DNA polymerases in the generation of mutations after exposure to genotoxic exposures. There are at least 14 bona fide DNA polymerases in mammalian cells, the majority of which do not have well defined roles in vivo. Many of the more recently discovered polymerases have unusual properties and are hypothesized to be specifically suited for a variety processes in vivo, including (so far) translesion DNA synthesis, non-homologous end joining, homologous recombination and somatic hypermutation. One polymerase in particular, pol eta, has been strongly implicated as being crucial for preventing mutations by the UV-light induced cis-syn cyclobutane pyrimidine dimer adduct, as evidenced by the extreme sunlight sensitivity displayed by Xeroderma pigmentosum variant patients who naturally lack the polymerase. However, pol eta displays low fidelity when bypassing this lesion. This has led to the idea that multiple factors are involved in the complete bypass reaction, including but not limited to proofreading, replication accessory proteins, and the mismatch DNA repair pathway. We study various aspects of several DNA polymerases (eta, iota, kappa, Rev1) in basic science research that involves protein purification, in vitro and in vivo DNA replication fidelity measurements, and cell based studies investigating how DNA polymerase expression and activity are altered after genotoxic exposures.
Research Areas: Mutagenesis, Polymerase Expression
Selected Publications:
McCulloch SD and Kunkel TA (2008) The fidelity of DNA synthesis by eukaryotic replicative and translesion synthesis polymerases. Cell Res 18:148-161.
Sakamoto AN, Stone JS, Kissling GE, McCulloch SD, Pavlov YI, and Kunkel TA (2007) Mutator alleles of yeast DNA polymerase zeta. DNA Repair 6:1829-1838.
McCulloch SD, Wood A, Garg P, Burgers PM, and Kunkel TA (2007) The effect of replication accessory proteins on the efficiency and fidelity of TT dimer bypass by S. cerevisiae pol eta . Biochemistry 46:8888-8896.
Barone F, McCulloch SD, Macpherson P, Maga G, Yamada M, Nohmi T, Minoprio A, Mazzei F, Kunkel TA, Karran P, and Bignami M (2007) Replication of 2-hydroxyadenine-containing DNA and recognition by human MutSalpha . DNA Repair , 6:355-66.
McCulloch SD and Kunkel TA (2006) Multiple solutions to inefficient lesion bypass by T7 DNA polymerase. DNA Repair 5:1373-1383.
Lin Q, Clark AB , McCulloch SD, Yuan T, Bronson RT, Kunkel TA, and Kucherlapati R (2006) Increased susceptibility to UV-induced skin carcinogenesis in polymerase eta-deficient mice. Cancer Res 66:87-94.
McCulloch SD and Kunkel TA (2006) Measuring the fidelity of translesion synthesis. Methods Enzymol 408:341-355.
McCulloch SD, Kokoska RJ, and Kunkel TA (2004) Efficiency, fidelity and enzymatic switching during translesion DNA synthesis. Cell Cycle 3:580-583.
McCulloch SD, Kokoska RJ, Chilkova O, Welch CM, Johansson E, Burgers PM, and Kunkel TA (2004) Enzymatic switching for efficient and accurate translesion DNA replication. Nucl Acids Res 32:4665-4675.
Wang M, Devereux TR, Vikis HG, McCulloch SD, Holliday W, Anna C, Wang Y, Bebenek K, Kunkel TA, Guan K, and You M (2004) Pol iota is a candidate for the mouse pulmonary adenoma resistance 2 locus, a major modifier of chemically induced lung neoplasia. Cancer Res 64:1924-1931.
McCulloch SD, Kokoska RJ, Masutani C, Iwai S, Hanaoka F, and Kunkel TA (2004) Preferential cis-syn thymine dimer bypass by DNA polymerase eta occurs with biased fidelity. Nature 428:97-100.
Kokoska RJ, McCulloch SD, and Kunkel TA (2003) The efficiency and specificity of apurinic/apyrimidinic site bypass by human DNA polymerase eta and Sulfolobus solfataricus Dpo4. J Biol Chem 278:50537-50545.
Glick E, Chau J, Vigna K, McCulloch SD, Adman E, Kunkel TA, and Loeb L (2003) Amino acid substitutions at conserved tyrosine 52 alter fidelity and bypass efficiency of human DNA polymerase eta . J Biol Chem 278:19341-19346.