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Gupta A, Hwang BJ, Benyamien-Roufaeil D, Jain S, Liu S, Gonzales R, Brown RA, Zalzman M, Lu AL, Lu AL. Mammalian MutY Homolog (MYH or MUTYH) is Critical for Telomere Integrity under Oxidative Stress. OBM GERIATRICS 2022; 6:196. [PMID: 35812693 PMCID: PMC9267527 DOI: 10.21926/obm.geriatr.2202196] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Telomeres consist of special features and proteins to protect the ends of each chromosome from deterioration and fusion. The telomeric DNA repeats are highly susceptible to oxidative damage that can accelerate telomere shortening and affect telomere integrity. Several DNA repair factors including MYH/MUTYH DNA glycosylase, its interacting partners Rad9/Rad1/Hus1 checkpoint clamp, and SIRT6 aging regulator, are associated with the telomeres. MYH prevents C:G to A:T mutation by removing adenine mispaired with a frequent oxidative DNA lesion, 8-oxoguanine. Here, we show that hMYH knockout (KO) human HEK-293T cells are more sensitive to H2O2 treatment, have higher levels of DNA strand breaks and shorter telomeres than the control hMYH +/+ cells. SIRT6 foci increase at both the global genome and at telomeric regions in H2O2-treated hMYH +/+ cells. However, in untreated hMYH KO HEK-293T cells, SIRT6 foci only increase at the global genome, but not at the telomeric regions. In addition, the hMYH KO HEK-293T cells have increased extra-chromosomal and intra-chromosomal telomeres compared to the control cells, even in the absence of H2O2 treatment. After H2O2 treatment, the frequency of extra-chromosomal telomeres increased in control HEK-293T cells. Remarkably, in H2O2-treated hMYH KO cells, the frequencies of extra-chromosomal telomeres, intra-chromosomal telomeres, and telomere fusions are further increased. We further found that the sensitivity to H2O2 and shortened telomeres of hMYH KO cells, are restored by expressing wild-type hMYH, and partially rescued by expressing hMYHQ324H mutant (defective in Hus1 interaction only), but not by expressing hMYHV315A mutant (defective in both SIRT6 and Hus1 interactions). Thus, MYH interactions with SIRT6 and Hus1 are critical for maintaining cell viability and telomeric stability. Therefore, the failure to coordinate 8-oxoG repair is detrimental to telomere integrity.
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Affiliation(s)
- Aditi Gupta
- University of Maryland School of Medicine, Baltimore, MD, USA
| | - Bor-Jang Hwang
- University of Maryland School of Medicine, Baltimore, MD, USA
| | | | - Sara Jain
- University of Maryland School of Medicine, Baltimore, MD, USA
| | - Sophie Liu
- University of Maryland School of Medicine, Baltimore, MD, USA
| | - Rex Gonzales
- University of Maryland School of Medicine, Baltimore, MD, USA
| | - Robert A Brown
- University of Maryland School of Medicine, Baltimore, MD, USA
| | - Michal Zalzman
- University of Maryland School of Medicine; The Center for Stem Cell Biology and Regenerative Medicine; Marlene and Stewart Greenbaum Cancer Center, Baltimore, MD 21201, USA
| | - A-Lien Lu
- University of Maryland School of Medicine; Marlene and Stewart Greenbaum Cancer Center, Baltimore, MD, USA
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Raetz AG, David SS. When you're strange: Unusual features of the MUTYH glycosylase and implications in cancer. DNA Repair (Amst) 2019; 80:16-25. [PMID: 31203172 DOI: 10.1016/j.dnarep.2019.05.005] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2019] [Revised: 05/23/2019] [Accepted: 05/29/2019] [Indexed: 02/06/2023]
Abstract
MUTYH is a base-excision repair glycosylase that removes adenine opposite 8-oxoguanine (OG). Variants of MUTYH defective in functional activity lead to MUTYH-associated polyposis (MAP), which progresses to cancer with very high penetrance. Whole genome and whole exome sequencing studies have found MUTYH deficiencies in an increasing number of cancer types. While the canonical OG:A repair activity of MUTYH is well characterized and similar to bacterial MutY, here we review more recent evidence that MUTYH has activities independent of OG:A repair and appear centered on the interdomain connector (IDC) region of MUTYH. We summarize evidence that MUTYH is involved in rapid DNA damage response (DDR) signaling, including PARP activation, 9-1-1 and ATR signaling, and SIRT6 activity. MUTYH alters survival and DDR to a wide variety of DNA damaging agents in a time course that is not consistent with the formation of OG:A mispairs. Studies that suggest MUTYH inhibits the repair of alkyl-DNA damage and cyclopyrimidine dimers (CPDs) is reviewed, and evidence of a synthetic lethal interaction with mismatch repair (MMR) is summarized. Based on these studies we suggest that MUTYH has evolved from an OG:A mispair glycosylase to a multifunctional scaffold for DNA damage response signaling.
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Affiliation(s)
- Alan G Raetz
- Department of Chemistry, University of California, Davis, Davis, CA, USA.
| | - Sheila S David
- Department of Chemistry, University of California, Davis, Davis, CA, USA.
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Banda DM, Nuñez NN, Burnside MA, Bradshaw KM, David SS. Repair of 8-oxoG:A mismatches by the MUTYH glycosylase: Mechanism, metals and medicine. Free Radic Biol Med 2017; 107:202-215. [PMID: 28087410 PMCID: PMC5457711 DOI: 10.1016/j.freeradbiomed.2017.01.008] [Citation(s) in RCA: 66] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/17/2016] [Revised: 01/01/2017] [Accepted: 01/04/2017] [Indexed: 12/12/2022]
Abstract
Reactive oxygen and nitrogen species (RONS) may infringe on the passing of pristine genetic information by inducing DNA inter- and intra-strand crosslinks, protein-DNA crosslinks, and chemical alterations to the sugar or base moieties of DNA. 8-Oxo-7,8-dihydroguanine (8-oxoG) is one of the most prevalent DNA lesions formed by RONS and is repaired through the base excision repair (BER) pathway involving the DNA repair glycosylases OGG1 and MUTYH in eukaryotes. MUTYH removes adenine (A) from 8-oxoG:A mispairs, thus mitigating the potential of G:C to T:A transversion mutations from occurring in the genome. The paramount role of MUTYH in guarding the genome is well established in the etiology of a colorectal cancer predisposition syndrome involving variants of MUTYH, referred to as MUTYH-associated polyposis (MAP). In this review, we highlight recent advances in understanding how MUTYH structure and related function participate in the manifestation of human disease such as MAP. Here we focus on the importance of MUTYH's metal cofactor sites, including a recently discovered "Zinc linchpin" motif, as well as updates to the catalytic mechanism. Finally, we touch on the insight gleaned from studies with MAP-associated MUTYH variants and recent advances in understanding the multifaceted roles of MUTYH in the cell, both in the prevention of mutagenesis and tumorigenesis.
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Affiliation(s)
- Douglas M Banda
- Department of Chemistry, University of California, Davis, One Shields Avenue, Davis, CA 95616, United States
| | - Nicole N Nuñez
- Department of Chemistry, University of California, Davis, One Shields Avenue, Davis, CA 95616, United States
| | - Michael A Burnside
- Department of Chemistry, University of California, Davis, One Shields Avenue, Davis, CA 95616, United States
| | - Katie M Bradshaw
- Department of Chemistry, University of California, Davis, One Shields Avenue, Davis, CA 95616, United States
| | - Sheila S David
- Department of Chemistry, University of California, Davis, One Shields Avenue, Davis, CA 95616, United States.
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