scholarly journals Structural studies on M. tuberculosis O6-methylguanine methyltransferase

2014 ◽  
Vol 70 (a1) ◽  
pp. C832-C832
Author(s):  
Menico Rizzi ◽  
Riccardo Miggiano ◽  
Samarpita Lahiri ◽  
Giuseppe Perugino ◽  
Maria Ciaramella ◽  
...  
Keyword(s):  
Excision Repair ◽  
Single Step ◽  
Double Stranded Dna ◽  
Nucleotide Excision ◽  
Enzymatic Systems ◽  
Methylguanine Methyltransferase ◽  
Mutagenic Effects ◽  
Wild Type Form

Mycobacterium tuberculosis (MTB) is an extremely well adapted human pathogen capable to survive for decades inside the hostile environment represented by the host's infected macrophages despite exposure to multiple potential DNA-damaging stresses. In order to maintain a remarkable low level of genetic diversity, MTB deploys different strategies of DNA repair, including multi-enzymatic systems, such as Nucleotide Excision Repair, and single-step repair. In particular, to counteract the mutagenic effects of DNA alkylation, MTB performs the direct alkylated-base reversal by sacrificing one molecule of a DNA-protein alkyltransferase, such as O6-methylguanine methyltransferase (OGT; orf: Rv1316c). We present here the biochemical and structural characterization of recombinant mycobacterial OGT (MtOGT) in its wild-type form along with its mutated variants mimicking the ones occurring in relevant clinical strains (i.e. MtOGT-T15S and MtOGT-R37L). Our studies reveal that MtOGT-R37L is severely impaired in its activity as consequence of its ten-fold lower affinity for modified double-stranded DNA (dsDNA) (1). Further investigations on a new structure-based panel of OGT versions, designed to explore different molecular environment at position 37, allowed us a better understanding of the functional role of the MtOGT Arg37-bearing loop during catalysis. Moreover, we solved the crystal structure of MtOGT in covalent complex with modified dsDNA that reveals an unprecedented MtOGT::DNA architecture, suggesting that the MtOGT monomer performing the catalysis needs assisting unreacted subunits during cooperative DNA binding. This work is supported by European Community FP7 program SYSTEMTB (Health-F4-2010-241587)

scholarly journals Identification and characterization of XPC-binding domain of hHR23B.

1997 ◽  
Vol 17 (12) ◽  
pp. 6915-6923 ◽  
Author(s):  
C Masutani ◽  
M Araki ◽  
K Sugasawa ◽  
P J van der Spek ◽  
A Yamada ◽  
...  
Keyword(s):  
Hydrophobic Interactions ◽  
Excision Repair ◽  
Binding Domain ◽  
Cell Extracts ◽  
Nucleotide Excision ◽  
Stimulation Of

hHR23B was originally isolated as a component of a protein complex that specifically complements nucleotide excision repair (NER) defects of xeroderma pigmentosum group C cell extracts in vitro and was identified as one of two human homologs of the Saccharomyces cerevisiae NER gene product Rad23. Recombinant hHR23B has previously been shown to significantly stimulate the NER activity of recombinant human XPC protein (rhXPC). In this study we identify and functionally characterize the XPC-binding domain of hHR23B protein. We prepared various internal as well as terminal deletion products of hHR23B protein in a His-tagged form and examined their binding with rhXPC by using nickel-chelating Sepharose. We demonstrate that a domain covering 56 amino acids of hHR23B is required for binding to rhXPC as well as for stimulation of in vitro NER reactions. Interestingly, a small polypeptide corresponding to the XPC-binding domain is sufficient to exert stimulation of XPC NER activity. Comparison with known crystal structures and analysis with secondary structure programs provided strong indications that the binding domain has a predominantly amphipathic alpha-helical character, consistent with evidence that the affinity with XPC is based on hydrophobic interactions. Our work shows that binding to XPC alone is required and sufficient for the role of hHR23B in in vitro NER but does not rule out the possibility that the protein has additional functions in vivo.

scholarly journals Deletion of the Nucleotide Excision Repair Gene Ercc1 Reduces Immunoglobulin Class Switching and Alters Mutations Near Switch Recombination Junctions

2004 ◽  
Vol 200 (3) ◽  
pp. 321-330 ◽  
Author(s):  
Carol E. Schrader ◽  
Joycelyn Vardo ◽  
Erin Linehan ◽  
Michael Z. Twarog ◽  
Laura J. Niedernhofer ◽  
...  
Keyword(s):  
B Cells ◽  
Excision Repair ◽  
Dna Lesions ◽  
Wild Type ◽  
Repair Gene ◽  
Class Switch ◽  
Double Stranded Dna ◽  
Nucleotide Excision

The structure-specific endonuclease ERCC1-XPF is an essential component of the nucleotide excision DNA repair pathway. ERCC1-XPF nicks double-stranded DNA immediately adjacent to 3′ single-strand regions. Substrates include DNA bubbles and flaps. Furthermore, ERCC1 interacts with Msh2, a mismatch repair (MMR) protein involved in class switch recombination (CSR). Therefore, ERCC1-XPF has abilities that might be useful for antibody CSR. We tested whether ERCC1 is involved in CSR and found that Ercc1−/− splenic B cells show moderately reduced CSR in vitro, demonstrating that ERCC1-XPF participates in, but is not required for, CSR. To investigate the role of ERCC1 in CSR, the nucleotide sequences of switch (S) regions were determined. The mutation frequency in germline Sμ segments and recombined Sμ-Sγ3 segments cloned from Ercc1−/− splenic B cells induced to switch in culture was identical to that of wild-type (WT) littermates. However, Ercc1−/− cells show increased targeting of the mutations to G:C bp in RGYW/WRCY hotspots and mutations occur at sites more distant from the S–S junctions compared with WT mice. The results indicate that ERCC1 is not epistatic with MMR and suggest that ERCC1 might be involved in processing or repair of DNA lesions in S regions during CSR.

scholarly journals The role of nucleotide excision repair in protecting embryonic stem cells from genotoxic effects of UV-induced DNA damage

1999 ◽  
Vol 27 (16) ◽  
pp. 3276-3282 ◽  
Author(s):  
P. P. H. Van Sloun ◽  
J. G. Jansen ◽  
G. Weeda ◽  
L. H. F. Mullenders ◽  
A. A. van Zeeland ◽  
...  
Keyword(s):  
Stem Cells ◽  
Dna Damage ◽  
Embryonic Stem Cells ◽  
Nucleotide Excision Repair ◽  
Excision Repair ◽  
Embryonic Stem ◽  
Genotoxic Effects ◽  
Nucleotide Excision

scholarly journals Nucleotide Excision Repair Protein Rad23 Regulates Cell Virulence Independent of Rad4 in Candida albicans

mSphere ◽  
2020 ◽  
Vol 5 (1) ◽  
Author(s):  
Jia Feng ◽  
Shuangyan Yao ◽  
Yansong Dong ◽  
Jing Hu ◽  
Malcolm Whiteway ◽  
...  
Keyword(s):  
Dna Damage ◽  
Candida Albicans ◽  
Nucleotide Excision Repair ◽  
Dna Damage Response ◽  
Excision Repair ◽  
Content Type ◽  
Virulence Regulation ◽  
Nucleotide Excision ◽  
Damage Response

ABSTRACT In the pathogenic yeast Candida albicans, the DNA damage response contributes to pathogenicity by regulating cell morphology transitions and maintaining survival in response to DNA damage induced by reactive oxygen species (ROS) in host cells. However, the function of nucleotide excision repair (NER) in C. albicans has not been extensively investigated. To better understand the DNA damage response and its role in virulence, we studied the function of the Rad23 nucleotide excision repair protein in detail. The RAD23 deletion strain and overexpression strain both exhibit UV sensitivity, confirming the critical role of RAD23 in the nucleotide excision repair pathway. Genetic interaction assays revealed that the role of RAD23 in the UV response relies on RAD4 but is independent of RAD53, MMS22, and RAD18. RAD4 and RAD23 have similar roles in regulating cell morphogenesis and biofilm formation; however, only RAD23, but not RAD4, plays a negative role in virulence regulation in a mouse model. We found that the RAD23 deletion strain showed decreased survival in a Candida-macrophage interaction assay. Transcriptome sequencing (RNA-seq) and quantitative real-time PCR (qRT-PCR) data further revealed that RAD23, but not RAD4, regulates the transcription of a virulence factor, SUN41, suggesting a unique role of RAD23 in virulence regulation. Taking these observations together, our work reveals that the RAD23-related nucleotide excision pathway plays a critical role in the UV response but may not play a direct role in virulence. The virulence-related role of RAD23 may rely on the regulation of several virulence factors, which may give us further understanding about the linkage between DNA damage repair and virulence regulation in C. albicans. IMPORTANCE Candida albicans remains a significant threat to the lives of immunocompromised people. An understanding of the virulence and infection ability of C. albicans cells in the mammalian host may help with clinical treatment and drug discovery. The DNA damage response pathway is closely related to morphology regulation and virulence, as well as the ability to survive in host cells. In this study, we checked the role of the nucleotide excision repair (NER) pathway, the key repair system that functions to remove a large variety of DNA lesions such as those caused by UV light, but whose function has not been well studied in C. albicans. We found that Rad23, but not Rad4, plays a role in virulence that appears independent of the function of the NER pathway. Our research revealed that the NER pathway represented by Rad4/Rad23 may not play a direct role in virulence but that Rad23 may play a unique role in regulating the transcription of virulence genes that may contribute to the virulence of C. albicans.

scholarly journals Variation in PAH-related DNA adduct levels among non-smokers: The role of multiple genetic polymorphisms and nucleotide excision repair phenotype

2012 ◽  
Vol 132 (12) ◽  
pp. 2738-2747 ◽  
Author(s):  
Arash Etemadi ◽  
Farhad Islami ◽  
David H. Phillips ◽  
Roger Godschalk ◽  
Asieh Golozar ◽  
...  
Keyword(s):  
Genetic Polymorphisms ◽  
Nucleotide Excision Repair ◽  
Excision Repair ◽  
Dna Adduct ◽  
Nucleotide Excision

CHAPTER 11. The Role of Chromatin and Chromatin-modifying Enzymes in Regulating Nucleotide Excision Repair

2021 ◽  
pp. 252-270
Author(s):  
Kathiresan Selvam ◽  
Dalton A. Plummer ◽  
Kaitlynne A. Bohm ◽  
John J. Wyrick
Keyword(s):  
Nucleotide Excision Repair ◽  
Excision Repair ◽  
Nucleotide Excision

scholarly journals Ubiquilin Networking in Cancers

Cancers ◽  
2020 ◽  
Vol 12 (6) ◽  
pp. 1586
Author(s):  
Salinee Jantrapirom ◽  
Luca Lo Piccolo ◽  
Dumnoensun Pruksakorn ◽  
Saranyapin Potikanond ◽  
Wutigri Nimlamool
Keyword(s):  
Cell Cycle ◽  
Genetic Variants ◽  
Epithelial Mesenchymal Transition ◽  
Excision Repair ◽  
Cancer Therapies ◽  
Cellular Functions ◽  
Mesenchymal Transition ◽  
Wide Range ◽  
Nucleotide Excision

Ubiquilins or UBQLNs, members of the ubiquitin-like and ubiquitin-associated domain (UBL-UBA) protein family, serve as adaptors to coordinate the degradation of specific substrates via both proteasome and autophagy pathways. The UBQLN substrates reveal great diversity and impact a wide range of cellular functions. For decades, researchers have been attempting to uncover a puzzle and understand the role of UBQLNs in human cancers, particularly in the modulation of oncogene’s stability and nucleotide excision repair. In this review, we summarize the UBQLNs’ genetic variants that are associated with the most common cancers and also discuss their reliability as a prognostic marker. Moreover, we provide an overview of the UBQLNs networks that are relevant to cancers in different ways, including cell cycle, apoptosis, epithelial-mesenchymal transition, DNA repairs and miRNAs. Finally, we include a future prospective on novel ubiquilin-based cancer therapies.

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