Influence of different inhibitors on the activity of theRAD54 dependent step of DNA repair inSaccharomyces cerevisiae

Siede, Wolfram; Obermaier, Sabine; Eckardt, F.

doi:10.1007/bf01212648

Cited by 8 publications

(4 citation statements)

References 14 publications

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“…This gene is a homolog of the U. Maydis Rec1 and may function not only in checkpoints but also in some aspects of recombinational repair (Carr, 1995;Lehmann, 1996). Finally, in Saccharomyces cerevisiae, a strong inhibitory e ect of ca eine on the RAD54 mediated repair was reported (Siede et al, 1985).…”

Section: Caffeine Radiosensitization In Yeastmentioning

confidence: 97%

Homologous recombination as a potential target for caffeine radiosensitization in mammalian cells: reduced caffeine radiosensitization in XRCC2 and XRCC3 mutants

et al. 2000

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The radiosensitizing e ect of ca eine has been associated with the disruption of multiple DNA damage-responsive cell cycle checkpoints, but several lines of evidence also implicate inhibition of DNA repair. The role of DNA repair inhibition in ca eine radiosensitization remains uncharacterized, and it is unknown which repair process, or lesion, is a ected. We show that a radiosensitive cell line, mutant for the RAD51 homolog XRCC2 and defective in homologous recombination repair (HRR), displays signi®cantly diminished ca eine radiosensitization that can be restored by expression of XRCC2. Despite the reduced radiosensitization, ca eine e ectively abrogates checkpoints in S and G2 phases in XRCC2 mutant cells indicating that checkpoint abrogation is not su cient for radiosensitization. Another radiosensitive line, mutant for XRCC3 and defective in HRR, similarly shows reduced ca eine radiosensitization. On the other hand, a radiosensitive mutant (irs-20) of DNA-PKcs with a defect in non-homologous endjoining (NHEJ) is radiosensitized by ca eine to an extent comparable to wild-type cells. In addition, rejoining of radiation-induced DNA DSBs, that mainly re¯ects NHEJ, remains una ected by ca eine in XRCC2 and XRCC3 mutants, or their wild-type counterparts. These observations suggest that ca eine targets steps in HRR but not in NHEJ and that abrogation of checkpoint response is not su cient to explain radiosensitization. Indeed, immortalized ®bro-blasts from AT patients show ca eine radiosensitization despite the checkpoint defects associated with ATM mutation. We propose that ca eine radiosensitization is mediated by inhibition of stages in DNA DSB repair requiring HRR and that checkpoint disruption contributes by allowing these DSBs to transit into irreparable states. Thus, checkpoints may contribute to genomic stability by promoting error-free HRR. Oncogene (2000) 19, 5788 ± 5800.

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Section: Caffeine Radiosensitization In Yeastmentioning

confidence: 97%

Homologous recombination as a potential target for caffeine radiosensitization in mammalian cells: reduced caffeine radiosensitization in XRCC2 and XRCC3 mutants

et al. 2000

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“…The tfb3 ts Strain Exhibits Caffeine Sensitivity-In eukaryotic cells, caffeine is known to adversely affect genomic stability, at least in part by inhibiting DNA repair and/or overriding DNA damage checkpoint controls (20,21). In an effort to determine whether UV radiation sensitivity could be increased by inclusion of caffeine in the growth media, we were surprised to observe that tfb3 ts failed to grow in the presence of the drug, whereas the isogenic wild-type strain grew normally (Fig.…”

Section: The Tfb3mentioning

confidence: 99%

Subunit Interactions in Yeast Transcription/Repair Factor TFIIH

Feaver¹,

Huang²,

Gileadi³

et al. 2000

Journal of Biological Chemistry

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A yeast strain harboring a temperature-sensitive allele of TFB3 (tfb3 ts ), the 38-kDa subunit of the RNA polymerase II transcription/nucleotide excision repair factor TFIIH, was found to be sensitive to ultraviolet (UV) radiation and defective for nucleotide excision repair in vitro. Interestingly, tfb3 ts failed to grow on medium containing caffeine. A comprehensive pairwise two-hybrid analysis between yeast TFIIH subunits identified novel interactions between Rad3 and Tfb3, Tfb4 and Ssl1, as well as Ssl2 and Tfb2. These interactions have facilitated a more complete model of the structure of TFIIH and the nucleotide excision repairosome.The yeast transcription/nucleotide excision repair (NER) 1 factor TFIIH has been extensively purified and characterized (1). Comprised of a total of nine individual subunits, holoTFIIH is unique among RNA polymerase II (RNAP II) initiation factors in that it possesses enzymatic activity (2, 3). The subunits Rad3 and Ssl2 endow holoTFIIH with bi-directional DNA helicase activity (3). TFIIH also has a kinase activity that phosphorylates the C-terminal domain of Rpb1, the largest subunit of yeast RNA polymerase II. Under some conditions holoTFIIH can dissociate into the seven-subunit coreTFIIH and the two subunit TFIIK subcomplexes (4). C-terminal domain kinase activity has been shown to reside in TFIIK (1, 5). The recent isolation of TFB2, TFB3, and TFB4 completed the cloning of genes encoding subunits of yeast TFIIH (6). All TFIIH subunits are encoded by essential genes and have highly conserved counterparts in humans (6).A requirement for yeast TFIIH in NER was first suggested by the identification of the well characterized DNA helicase and NER protein Rad3 as a subunit of core TFIIH (3). This requirement was subsequently demonstrated directly using an in vitro NER assay (7). To date, viable or conditional mutants of all the subunits of coreTFIIH except Tfb3 have been used to demonstrate a role for these polypeptides in NER (6 -9). In contrast to core TFIIH, a requirement for TFIIK in NER has not been demonstrated. In this study we report the generation of a yeast strain with a temperature-sensitive allele of TFB3 (tfb3 ts ). This strain is sensitive to ultraviolet (UV) radiation in vivo and defective for NER in vitro. We conclude that Tfb3, like all coreTFIIH subunits, is indispensable for NER.A form of TFIIH has been identified that is associated with all of the other polypeptides known to be required for the early steps of NER in the absence of DNA damage. This large, preformed "super complex" is referred to as the nucleotide excision repairosome (4, 10). A number of earlier studies used a variety of approaches to reveal interactions between TFIIH and/or repairosome subunits (see references in Table II). The cloning of genes encoding the Tfb2, Tfb3, and Tfb4 polypeptides has facilitated the inclusion of these subunits as well. We report here two-hybrid interactions between Ssl2 and Tfb2, Rad3 and Tfb3, and Tfb4 and Ssl1. Based on these interactions together with those previo...

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“…These early studies incriminated caffeine as an inhibitor of DNA repair mechanisms but without relating the caffeine sensitivity with the DNA repair pathways. In subsequent studies, a pronounced inhibitory effect of caffeine on the Rad54-dependent repair of UV-irradiation damage was reported, an inhibition that was strongly dependent on the concentration of caffeine [ 41 ]. Later, other research groups confirmed the dose-dependent inhibitory effect of caffeine on the Rad54-dependent repair of UV-irradiation damage [ 42 , 43 ].…”

Section: Caffeine: Between Radio-protector and Radio-sensitizermentioning

confidence: 99%

“…A slight caffeine-sensitizing effect was found for the rad5l and rad54 mutants, which show defects in the repair of X-ray induced damage [ 45 ]. The results suggested that caffeine enhanced radiation-induced cell killing and that the caffeine-sensitive process involved in the repair of γ-ray-induced lesions interfered with a recombinational repair mechanism occurring in cells in S or G2 phase [ 41 ].…”

Section: Caffeine: Between Radio-protector and Radio-sensitizermentioning

confidence: 99%

Saccharomyces cerevisiae and Caffeine Implications on the Eukaryotic Cell

Ruţă

Fărcăşanu

2020

Nutrients

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Caffeine–a methylxanthine analogue of the purine bases adenine and guanine–is by far the most consumed neuro-stimulant, being the active principle of widely consumed beverages such as coffee, tea, hot chocolate, and cola. While the best-known action of caffeine is to prevent sleepiness by blocking the adenosine receptors, caffeine exerts a pleiotropic effect on cells, which lead to the activation or inhibition of various cell integrity pathways. The aim of this review is to present the main studies set to investigate the effects of caffeine on cells using the model eukaryotic microorganism Saccharomyces cerevisiae, highlighting the caffeine synergy with external cell stressors, such as irradiation or exposure to various chemical hazards, including cigarette smoke or chemical carcinogens. The review also focuses on the importance of caffeine-related yeast phenotypes used to resolve molecular mechanisms involved in cell signaling through conserved pathways, such as target of rapamycin (TOR) signaling, Pkc1-Mpk1 mitogen activated protein kinase (MAPK) cascade, or Ras/cAMP protein kinase A (PKA) pathway.

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Influence of different inhibitors on the activity of theRAD54 dependent step of DNA repair inSaccharomyces cerevisiae

Cited by 8 publications

References 14 publications

Homologous recombination as a potential target for caffeine radiosensitization in mammalian cells: reduced caffeine radiosensitization in XRCC2 and XRCC3 mutants

Homologous recombination as a potential target for caffeine radiosensitization in mammalian cells: reduced caffeine radiosensitization in XRCC2 and XRCC3 mutants

Subunit Interactions in Yeast Transcription/Repair Factor TFIIH

Saccharomyces cerevisiae and Caffeine Implications on the Eukaryotic Cell

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