The diploid human genome has been estimated to contain 6 billion nucleotides. It is an enormous task for the proliferating cell to replicate the entire genome, due to the size and accuracy by which it must be accomplished. It must also be a very efficient process because the cell has a very limited time to finish the task. We are studying on the molecular level how DNA replication is accomplished in eukaryotic cells. There still remain many large questions that have not been completely resolved. It is not entirely known how DNA replication is initiated, or how a replication fork functions. We are focused on the proteins that participate at the eukaryotic replication fork. Our main focus lies on DNA polymerase epsilon that plays a role at the replication fork.
Our main goals are, (i) to understand how DNA polymerase epsilon interacts with other replication fork proteins, (ii) to understand how DNA polymerase epsilon participates at the replication fork and if DNA polymerase epsilon fulfills some other important function during the replication of the chromosomes, (iii) to understand how DNA polymerase epsilon contributes to the fidelity of the replication of the genome, (iv) to understand how DNA polymerase epsilon is involved in DNA repair processes and cell-cycle regulation. Our model system is S. cerevisiae and this allows us to complement our biochemical characterizations with yeast genetics in in vivo experiments.
Josy ter Beek
ter Beek, J., Parkash, V., Bylund, G.O., Osterman, P., Sauer-Eriksson, A.E., and Johansson, E. (2019) Structural evidence for an essential Fe-S cluster in the catalytic core domain of DNA polymerase ε. Nucleic Acids Res 47:5712-5722
Parkash, V., Kulkarni, Y., ter Beek, J., Shcherbakova, P.V., Kamerlin, S.C.L., and Johansson, E. (2019) Structural consequence of the most frequently recurring cancer-associated substitution in DNA polymerase ε. Nature Communications 10:373
Yu, C., Gan, H., Serra-Cardona, A., Zhang, L., Gan, S., Sharma, S., Johansson, E., Chabes, A., Xu, R.-M., and Zhang, Z. (2018) A mechanism for preventing asymmetric histone segregation onto replicating DNA strands. Science 361:1386-1389
Ganai, R.A., and Johansson, E. (2016) DNA replication – a matter of fidelity. Molecular Cell 62: 745-755 Invited review
Hogg, M., Osterman, P., Bylund, G.O., Ganai, R.A., Lundström, E.-B., Sauer- Eriksson, A.E. and Johansson, E. (2014) Structural basis for processive DNA synthesis by yeast DNA polymerase ε. Nature Structural & Molecular Biology 21:49-55
Aksenova, A., Volkov, K., Macheluch, J., Pursell, Z.F., Rogozin, I.B., Kunkel, T.A., Pavlov, Y.I. and Johansson, E. (2010) Mismatch repair-independent increase in spontaneous mutagenesis in yeast lacking non-essential subunits of DNA polymerase epsilon. PLoS Genetics 6:e1001209
Chilkova, O., Stenlund, P., Isoz, I., Stith, C.M., Grabowski, P.M., Lundström, E-B., Burgers, P.M., and Johansson, E. (2007) The eukaryotic leading and lagging strand DNA polymerases are loaded onto the primer-end via separate mechanisms but have comparable processivity in the presence of PCNA. Nucleic Acids Res. 35: 6588 – 6597
Pursell, Z.F., Isoz, I., Lundström, E.-B., Johansson, E., and Kunkel, T.A. (2007) Yeast DNA polymerase epsilon participates in leading-strand DNA replication. Science 317: 127-130