Presentation Title

REGULATION OF TRANSLESION SYNTHESIS POLYMERASES ETA AND KAPPA IN RESPONSE TO DNA REPLICATION STRESS

Faculty Mentor

Tony Huang

Start Date

17-11-2018 9:00 AM

End Date

17-11-2018 9:15 AM

Location

C158

Session

Oral 1

Type of Presentation

Oral Talk

Subject Area

biological_agricultural_sciences

Abstract

The cell faces constant pressures from exogenous and endogenous factors that damage DNA. During DNA replication, when the replisome encounters damaged DNA it causes replication stress - the slowing or stopping of DNA replication machinery. Excessive replication stress can cause a host of complications like gene translocations and apoptosis. Thus, the cell has developed mechanisms to tolerate DNA damages during DNA replication by using translesion synthesis (TLS) polymerases. TLS polymerases are able to replicate DNA in the presence of different forms of DNA damage and allow the replisome to bypass DNA lesions. The Y-family polymerases are a group of TLS polymerases which are functionally and structurally similar but exhibit preferences for different types of lesions. However, the mechanism that controls the regulation of different TLS polymerase usage has not been well elucidated. The goal of this project is to elucidate how the Y-family TLS polymerases Eta and Kappa are regulated in response to replication stress. We exposed cells to different replicative stressors - UV light and Hydroxyurea, a drug which reduces nucleotide levels - then used western blotting to analyze the effect of these treatments on TLS polymerase expression and various markers for cell stress and DNA damage. Interestingly, in response to UV, Pol Kappa and is degraded in a proteasome dependent manner, suggesting that specific degradation may regulate TLS polymerase usage. The study of the regulation of DNA damage tolerance will aid in understanding the role of this phenomenon in cancer, which could help potentiate existing genotoxic cancer therapies.

Summary of research results to be presented

Here we show that translesion synthesis polymerase, Pol Kappa levels within the cell are reduced in response to UV irradiation and this reduction is mitigated by protoeosome inhibitor (mg132) suggesting that this reduction is mediated by the protoeosome. We also show that the E3 ligase responsible for mediating this effect is not a Cullin Ring Ligase.

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Nov 17th, 9:00 AM Nov 17th, 9:15 AM

REGULATION OF TRANSLESION SYNTHESIS POLYMERASES ETA AND KAPPA IN RESPONSE TO DNA REPLICATION STRESS

C158

The cell faces constant pressures from exogenous and endogenous factors that damage DNA. During DNA replication, when the replisome encounters damaged DNA it causes replication stress - the slowing or stopping of DNA replication machinery. Excessive replication stress can cause a host of complications like gene translocations and apoptosis. Thus, the cell has developed mechanisms to tolerate DNA damages during DNA replication by using translesion synthesis (TLS) polymerases. TLS polymerases are able to replicate DNA in the presence of different forms of DNA damage and allow the replisome to bypass DNA lesions. The Y-family polymerases are a group of TLS polymerases which are functionally and structurally similar but exhibit preferences for different types of lesions. However, the mechanism that controls the regulation of different TLS polymerase usage has not been well elucidated. The goal of this project is to elucidate how the Y-family TLS polymerases Eta and Kappa are regulated in response to replication stress. We exposed cells to different replicative stressors - UV light and Hydroxyurea, a drug which reduces nucleotide levels - then used western blotting to analyze the effect of these treatments on TLS polymerase expression and various markers for cell stress and DNA damage. Interestingly, in response to UV, Pol Kappa and is degraded in a proteasome dependent manner, suggesting that specific degradation may regulate TLS polymerase usage. The study of the regulation of DNA damage tolerance will aid in understanding the role of this phenomenon in cancer, which could help potentiate existing genotoxic cancer therapies.