Projects in the Trakselis laboratory center on understanding the molecular mechanisms of DNA replication and repair and exploiting this knowledge for a better understanding of replisome progression, cancer predisposition, biotechnology applications, and fertility.

 

DNA POLYMERASE SUBSTITUTIONS AT LESIONS
Although it is known the lower fidelity DNA polymerases are recruited to replicate over specific types of DNA damage for translesion synthesis (TLS), the mechanisms for swapping a high-fidelity polymerase for a TLS polymerase is not known. We are utilizing enzymes from both Archaea and humans to mechanistically describe and compare this process between domains. We are focusing on molecular contacts, inherent kinetics, and thermodynamic equilibria to allow efficient exchange or switching of DNA polymerases at lesion sites.

HEXAMERIC HELICASE UNWINDING MECHANISMS
Hexameric helicases are known to track along one DNA strand and physically exclude the other for efficient DNA unwinding that occurs during DNA replication. We are interested in better understanding the molecular process of DNA unwinding by hexameric helicases and how coupling of DNA unwinding and synthesis is maintained. The coordinated activities of DNA helicases and polymerases ensure that single-stranded DNA does not build up and is required for a stable genome.

CHARACTERIZING MCM8/9 FUNCTION IN HIGHER EUKARYOTES
Although much effort has been aimed at understanding the role of MCM2-7 in DNA replication initiation, MCM8 and MCM9, paralogs of MCM2, have also recently been implicated in aiding replisome progression, protecting stalled forks, and facilitating recombination. These proteins are not found in lower eukaryotes such as yeast or C. elegans; so, its function has evolved only in higher eukaryotes. We are currently examining the role of MCM8/9 in human cells with regards to structure/function, DNA substrate specificity, and temporal role in maintaining replications fork stability. Mutations in MCM8 or MCM9 are commonly linked to infertility, ovarian insufficiency and failure, as well as cancer.

PROTEIN-DNA COMPLEXES IN THE GAS PHASES
A new project in the lab seeks to examine protein-DNA complexes in the gas phase, bu utilizing advance mass spectrometry techniques. In collaboration with the Gallagher lab, we are interested in measuring protein stabilities, coooperativities, and structural conformations of diverse single-stranded DNA binding protein complexes.