Dysfunction of human Rad18 results in defective postreplication repair and hypersensitivity to multiple mutagens

Tateishi, Seiichiro; Sakuraba, Yoshiyuki; Masuyama, Sadaharu; Inoue, Hirokazu; Yamaizumi, Masaru

doi:10.1073/pnas.97.14.7927

Cited by 131 publications

(143 citation statements)

References 22 publications

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“…However, the possibility that hRad18 titrates the human homologues of Rad6 is unlikely since it has been reported that the RING finger of hRad18 is necessary for hRad6A/B-hRad18 binding (34). Our deletion analysis showed that the RING finger motif does not play an essential role in the interaction between hRad18 and HIV-1 integrase, ruling out a direct competition between HIV-1 integrase and hRad6A/B for hRad18 binding.…”

Section: Discussionmentioning

confidence: 79%

Interaction of HIV-1 Integrase with DNA Repair Protein hRad18

Mulder

Chakrabarti²,

Muesing

2002

Journal of Biological Chemistry

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We have previously shown that human immunodeficiency virus-1 (HIV-1) integrase is an unstable protein and a substrate for the N-end rule degradation pathway. This degradation pathway shares its ubiquitin-conjugating enzyme, Rad6, with the post-replication/translesion DNA repair pathway. Because DNA repair is thought to play an essential role in HIV-1 integration, we investigated whether other molecules of this DNA repair pathway could interact with integrase. We observed that co-expression of human Rad18 induced the accumulation of an otherwise unstable form of HIV-1 integrase. This accumulation occurred even though hRAD18 possesses a RING finger domain, a structure that is generally associated with E3 ubiquitin ligase function and protein degradation. Evidence for an interaction between integrase and hRad18 was obtained through reciprocal co-immunoprecipitation. Moreover we found that a 162-residue region of hRad18 (amino acids 65-226) was sufficient for both integrase stabilization and interaction. Finally, we observed that HIV-1 integrase co-localized with hRad18 in nuclear structures in a subpopulation of co-transfected cells. Taken together, these findings identify hRad18 as a novel interacting partner of HIV-1 integrase and suggest a role for post-replication/translesion DNA repair in the retroviral integration process.

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Section: Discussionmentioning

confidence: 79%

Interaction of HIV-1 Integrase with DNA Repair Protein hRad18

Mulder

Chakrabarti²,

Muesing

2002

Journal of Biological Chemistry

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“…Genetic studies of Saccharomyces cerevisiae suggest that all known components of TLS belong to the epistasis group of the RAD6-RAD18 genes (21,22), which are conserved from yeast to mammalian cells (23)(24)(25)(26)(27). The Rad6 protein is one of the ubiquitin-conjugating enzymes (E2s) and forms a tight complex with the Rad18 protein, which may have E3 ubiquitin ligase activity (28,29 lymphocyte line DT40 (30).…”

mentioning

confidence: 99%

Involvement of Vertebrate Polκ in Rad18-independent Postreplication Repair of UV Damage

Okada¹,

Sonoda²,

Yamashita³

et al. 2002

Journal of Biological Chemistry

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DNA damage, which is left unrepaired by excision repair pathways, often blocks replication, leading to lesions such as breaks and gaps on the sister chromatids. These lesions may be processed by either homologous recombination (HR) repair or translesion DNA synthesis (TLS). Vertebrate Pol belongs to the DNA polymerase Y family, as do most TLS polymerases. However, the role for Pol in vertebrate cells is unclear because of the lack of reverse genetic studies. Here, we generated cells deficient in Pol (pol cells) from the chicken B lymphocyte line DT40. Although purified Pol is unable to bypass ultraviolet (UV) damage, pol cells exhibited increased UV sensitivity, and the phenotype was suppressed by expression of human and chicken Pol, suggesting that Pol is involved in TLS of UV photoproduct. Defects in both Pol and Rad18, which regulates TLS in yeast, in DT40 showed an additive effect on UV sensitivity. Interestingly, the level of sister chromatid exchange, which reflects HR-mediated repair, was elevated in normally cycling pol cells. This implies functional redundancy between HR and Pol in maintaining chromosomal DNA. In conclusion, vertebrate Pol is involved in Rad18-independent TLS of UV damage and plays a role in maintaining genomic stability.A wide range of potential insult to the genomic DNA is contributed not only by the environment, but also by cellular activities. DNA damages, which are left unrepaired by excision repair pathways, may arrest DNA replication, leading to breaks and gaps on the sister chromatids. These lesions are processed by two major postreplication repair pathways: homologous recombination (HR) 1 repair and translesion DNA synthesis (TLS) (1). TLS fills a daughter strand gap that encompasses a DNA damage on the template strand by employing a number of specialized DNA polymerases (Pols) (reviewed in Refs. 2-4). On the other hand, HR functions in processing both gaps and breaks by facilitating recombination between damaged sister chromatids with the other intact ones. Thus, daughter-strand gaps can be processed by both TLS and HR in postreplicational repair.Human cells contain four Y family DNA polymerases, namely Pol (Rad30A), Pol (Rad30B), Pol (DinB1), and Rev1 (5-7). A number of biochemical studies have demonstrated that Y family DNA polymerases can bypass specific lesions on the template strand (8 -12), whereas in vivo function of these polymerases are as yet unclear except for Pol. Pol is mutated in a variant form of xeroderma pigmentosum (XP-V) (13, 14), which is characterized by predisposition to skin cancer and elevated UV sensitivity.

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“…Mouse and human Rad18 are able to interact with both HR6A and HR6B protein (Tateishi et al, 2000;Xin et al, 2000). As in budding yeast, disruption of RAD18 in human cells or in DT40 chicken lymphocyte results in sensitivity to a variety of DNA-damaging agents (Yamashita et al, 2002).…”

Section: Rad18mentioning

confidence: 99%