Presentation Title

Disorderly Conduct: Investigating Unstructured Sequence Inserts of Human DNA Polymerase Theta

Abstract

After treatment with ionizing radiation, cancer cells must evade death by repairing the damage. This can involve DNA polymerase theta (pol theta), an error-prone DNA double-strand break (DSB) repair protein which functions through an alternative end-joining pathway termed theta-mediated end joining (TMEJ). TMEJ is a last resort pathway for DSB repair when the preferred homologous recombination (HR) and non-homologous end joining pathways are impaired. Upregulation of pol theta in breast cancer, non-small cell lung cancer, and oral squamous cell carcinoma is correlated with poor patient survival. In cancer cells with defective HR, inhibition of pol theta could be a useful adjuvant to ionizing radiation and other DNA-damaging cancer treatments. To achieve this goal, it is important to first identify the unique structural elements of pol theta that enable its specialized function. The C-terminal DNA synthesis domain harbors five disordered regions, not seen in lower eukaryotes, which affect both the overall structure and polymerase activity.

Here, we use a powerful combination of biochemistry, X-ray crystallography, fluorescence-based DNA synthesis assays, dynamic light scattering, and size exclusion chromatography to study the structure and activity of pol theta mutants informed by the structure, as well as cancer variants.

Primary Faculty Mentor Name

Sylvie Doublié

Status

Graduate

Student College

Larner College of Medicine

Program/Major

Cellular, Molecular and Biomedical Sciences

Primary Research Category

Biological Sciences

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Disorderly Conduct: Investigating Unstructured Sequence Inserts of Human DNA Polymerase Theta

After treatment with ionizing radiation, cancer cells must evade death by repairing the damage. This can involve DNA polymerase theta (pol theta), an error-prone DNA double-strand break (DSB) repair protein which functions through an alternative end-joining pathway termed theta-mediated end joining (TMEJ). TMEJ is a last resort pathway for DSB repair when the preferred homologous recombination (HR) and non-homologous end joining pathways are impaired. Upregulation of pol theta in breast cancer, non-small cell lung cancer, and oral squamous cell carcinoma is correlated with poor patient survival. In cancer cells with defective HR, inhibition of pol theta could be a useful adjuvant to ionizing radiation and other DNA-damaging cancer treatments. To achieve this goal, it is important to first identify the unique structural elements of pol theta that enable its specialized function. The C-terminal DNA synthesis domain harbors five disordered regions, not seen in lower eukaryotes, which affect both the overall structure and polymerase activity.

Here, we use a powerful combination of biochemistry, X-ray crystallography, fluorescence-based DNA synthesis assays, dynamic light scattering, and size exclusion chromatography to study the structure and activity of pol theta mutants informed by the structure, as well as cancer variants.