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Simple Summary: Human papillomavirus (HPV) causes 5% of cancers and is the main cause of oropharyngeal cancer in the United States and of cervical cancer worldwide. HPV proteins induce DNA damage and exploit and hijack the host DNA damage response. The HPV oncoproteins E6 and E7 induce chromosomal instability (CIN), or chromosome missegregation during mitosis, which also causes DNA damage and can lead to profound genetic alterations in the host cell. Though these features are known to contribute to HPV-induced carcinogenesis, how this affects tumor cell response to DNA damaging treatments is not well understood. Here, we review how HPV induces DNA damage and activates the DNA damage response and how the HPV-induced CIN likely exacerbates this. We then discuss how this viral protein-mediated DNA damage may affect the efficacy of chemoradiation therapy. High-risk human papillomaviruses (HPVs) are the main cause of cervical, oropharyngeal, and anogenital cancers, which are all treated with definitive chemoradiation therapy when locally advanced. HPV proteins are known to exploit the host DNA damage response to enable viral replication and the epithelial differentiation protocol. This has far-reaching consequences for the host genome, as the DNA damage response is critical for the maintenance of genomic stability. HPV+ cells therefore have increased DNA damage, leading to widespread genomic instability, a hallmark of cancer, which can contribute to tumorigenesis. Following transformation, high-risk HPV oncoproteins induce chromosomal instability, or chromosome missegregation during mitosis, which is associated with a further increase in DNA damage, particularly due to micronuclei and double-strand break formation. Thus, HPV induces significant DNA damage and activation of the DNA damage response in multiple contexts, which likely affects radiation sensitivity and efficacy. Here, we review how HPV activates the DNA damage response, how it induces chromosome missegregation and micronuclei formation, and discuss how these factors may affect radiation response. Understanding how HPV affects the DNA damage response in the context of radiation therapy may help determine potential mechanisms to improve therapeutic response. [ABSTRACT FROM AUTHOR]

Damage to DNA is common and can arise from numerous environmental and endogenous sources. In response to ubiquitous DNA damage, Y-family DNA polymerases are induced by the SOS response and are capable of bypassing DNA lesions. In Escherichia coli, these Y-family polymerases are DinB and UmuC, whose activities are modulated by their interaction with the polymerase manager protein UmuD. Many, but not all, bacteria utilize DinB and UmuC homologs. Recently, a C-family polymerase named ImuC, which is similar in primary structure to the replicative DNA polymerase DnaE, was found to be able to copy damaged DNA and either carry out or suppress mutagenesis. ImuC is often found with proteins ImuA and ImuB, the latter of which is similar to Y-family polymerases, but seems to lack the catalytic residues necessary for polymerase activity. This imuAimuBimuC mutagenesis cassette represents a widespread alternative strategy for translesion synthesis and mutagenesis in bacteria. Bacterial Y-family and ImuC DNA polymerases contribute to replication past DNA damage and the acquisition of antibiotic resistance. [ABSTRACT FROM AUTHOR]