Emerging roles for centromere-associated proteins in DNA repair and genetic recombination

2013 ◽  
Vol 41 (6) ◽  
pp. 1726-1730 ◽  
Author(s):  
Fekret Osman ◽  
Matthew C. Whitby
Keyword(s):  
Dna Repair ◽  
Homologous Recombination ◽  
Genetic Recombination ◽  
Current Knowledge ◽  
Complementation Group ◽  
Histone Fold ◽  
Centromere Proteins ◽  
Associated Proteins ◽  
And Function ◽  
Dna Translocase

Centromere proteins CENP-S and CENP-X are members of the constitutive centromere-associated network, which is a conserved group of proteins that are needed for the assembly and function of kinetochores at centromeres. Intriguingly CENP-S and CENP-X have alter egos going by the names of MHF1 (FANCM-associated histone-fold protein 1) and MHF2 respectively. In this guise they function with a DNA translocase called FANCM (Fanconi’s anemia complementation group M) to promote DNA repair and homologous recombination. In the present review we discuss current knowledge of the biological roles of CENP-S and CENP-X and how their dual existence may be a common feature of CCAN (constitutive centromere-associated network) proteins.

scholarly journals MHF1–2/CENP-S-X performs distinct roles in centromere metabolism and genetic recombination

Open Biology ◽  
2013 ◽  
Vol 3 (9) ◽  
pp. 130102 ◽  
Author(s):  
Sonali Bhattacharjee ◽  
Fekret Osman ◽  
Laura Feeney ◽  
Alexander Lorenz ◽  
Claire Bryer ◽  
...  
Keyword(s):  
Dna Repair ◽  
Chromosome Segregation ◽  
Genetic Recombination ◽  
Dual Function ◽  
Histone Fold ◽  
Chromosome Missegregation ◽  
Kinetochore Assembly ◽  
Dna Junctions ◽  
And Function ◽  
Dna Translocase

The histone-fold proteins Mhf1/CENP-S and Mhf2/CENP-X perform two important functions in vertebrate cells. First, they are components of the constitutive centromere-associated network, aiding kinetochore assembly and function. Second, they work with the FANCM DNA translocase to promote DNA repair. However, it has been unclear whether there is crosstalk between these roles. We show that Mhf1 and Mhf2 in fission yeast, as in vertebrates, serve a dual function, aiding DNA repair/recombination and localizing to centromeres to promote chromosome segregation. Importantly, these functions are distinct, with the former being dependent on their interaction with the FANCM orthologue Fml1 and the latter not. Together with Fml1, they play a second role in aiding chromosome segregation by processing sister chromatid junctions. However, a failure of this activity does not manifest dramatically increased levels of chromosome missegregation due to the Mus81–Eme1 endonuclease, which acts as a failsafe to resolve DNA junctions before the end of mitosis.

scholarly journals The VEGF receptor neuropilin 2 promotes homologous recombination by stimulating YAP/TAZ-mediated Rad51 expression

2019 ◽  
Vol 116 (28) ◽  
pp. 14174-14180 ◽  
Author(s):  
Ameer L. Elaimy ◽  
John J. Amante ◽  
Lihua Julie Zhu ◽  
Mengdie Wang ◽  
Charlotte S. Walmsley ◽  
...  
Keyword(s):  
Dna Repair ◽  
Homologous Recombination ◽  
Strand Break ◽  
Vegf Receptor ◽  
Vegf Signaling ◽  
Dna Double Strand Break ◽  
Essential Enzyme ◽  
And Function ◽  
Platinum Chemotherapy ◽  
Endothelial Growth Factor

Vascular endothelial growth factor (VEGF) signaling in tumor cells mediated by neuropilins (NRPs) contributes to the aggressive nature of several cancers, including triple-negative breast cancer (TNBC), independently of its role in angiogenesis. Understanding the mechanisms by which VEGF–NRP signaling contributes to the phenotype of such cancers is a significant and timely problem. We report that VEGF–NRP2 promote homologous recombination (HR) in BRCA1 wild-type TNBC cells by contributing to the expression and function of Rad51, an essential enzyme in the HR pathway that mediates efficient DNA double-strand break repair. Mechanistically, we provide evidence that VEGF–NRP2 stimulates YAP/TAZ-dependent Rad51 expression and that Rad51 is a direct YAP/TAZ–TEAD transcriptional target. We also discovered that VEGF–NRP2–YAP/TAZ signaling contributes to the resistance of TNBC cells to cisplatin and that Rad51 rescues the defects in DNA repair upon inhibition of either VEGF–NRP2 or YAP/TAZ. These findings reveal roles for VEGF–NRP2 and YAP/TAZ in DNA repair, and they indicate a unified mechanism involving VEGF–NRP2, YAP/TAZ, and Rad51 that contributes to resistance to platinum chemotherapy.

scholarly journals Genetic Recombination in Bacillus subtilis 168: Effect of ΔhelD on DNA Repair and Homologous Recombination

2001 ◽  
Vol 183 (19) ◽  
pp. 5772-5777 ◽  
Author(s):  
Begoña Carrasco ◽  
Silvia Fernández ◽  
Marie-Agnes Petit ◽  
Juan C. Alonso
Keyword(s):  
Dna Repair ◽  
Bacillus Subtilis ◽  
Homologous Recombination ◽  
Genetic Recombination ◽  
Methyl Methanesulfonate ◽  
Plasmid Transformation ◽  
Dna Damaging Agents ◽  
Bacillus Subtilis 168 ◽  
Recombination Repair ◽  
Helicase Iv

ABSTRACT The B. subtilis ΔhelD allele rendered cells proficient in transformational recombination and moderately sensitive to methyl methanesulfonate when present in an otherwise Rec+ strain. The ΔhelD allele was introduced into rec-deficient strains representative of the α (recF strain), β (addA addB), γ (recH), ɛ (ΔrecU), and ζ (ΔrecS) epistatic groups. The ΔhelDmutation increased the sensitivity to DNA-damaging agents ofaddAB, ΔrecU, and ΔrecS cells, did not affect the survival ofrecH cells, and decreased the sensitivity ofrecF cells. ΔhelD also partially suppressed the DNA repair phenotype of other mutations classified within the α epistatic group, namely the recL, ΔrecO, and recR mutations. The ΔhelD allele marginally reduced plasmid transformation (three- to sevenfold) of mutations classified within the α, β, and γ epistatic groups. Altogether, these data indicate that the loss of helicase IV might stabilize recombination repair intermediates formed in the absence of recFLOR and renderrecFLOR, addAB, andrecH cells impaired in plasmid transformation.

scholarly journals Multifunctional Involvement of a C2H2 Zinc Finger Protein (PbZfp) in Malaria Transmission, Histone Modification, and Susceptibility to DNA Damage Response

mBio ◽  
2017 ◽  
Vol 8 (4) ◽  
Author(s):  
Anusha M. Gopalakrishnan ◽  
Ahmed S. I. Aly ◽  
L. Aravind ◽  
Nirbhay Kumar
Keyword(s):  
Dna Damage ◽  
Dna Repair ◽  
Homologous Recombination ◽  
Zinc Finger ◽  
Plasmodium Berghei ◽  
Zinc Finger Protein ◽  
Genetic Recombination ◽  
Mosquito Vector ◽  
Histone 3 ◽  
Finger Protein

ABSTRACT In sexually reproducing organisms, meiosis is an essential step responsible for generation of haploid gametes from diploid somatic cells. The quest for understanding regulatory mechanisms of meiotic recombination in Plasmodium led to identification of a gene encoding a protein that contains 11 copies of C 2 H 2 zinc fingers (ZnF). Reverse genetic approaches were used to create Plasmodium berghei parasites either lacking expression of full-length Plasmodium berghei zinc finger protein (PbZfp) (knockout [KO]) or expressing PbZfp lacking C-terminal zinc finger region (truncated [Trunc]). Mice infected with KO parasites survived two times longer ( P < 0.0001) than mice infected with wild-type (WT) parasites. In mosquito transmission experiments, the infectivity of KO and Trunc parasites was severely compromised (>95% oocyst reduction). KO parasites revealed a total lack of trimethylation of histone 3 at several lysine residues (K4, K27, and K36) without any effect on acetylation patterns (H3K9, H3K14, and H4K16). Reduced DNA damage and reduced expression of topoisomerase-like Spo11 in the KO parasites with normal Rad51 expression further suggest a functional role for PbZfp during genetic recombination that involves DNA double-strand break (DSB) formation followed by DNA repair. These finding raise the possibility of some convergent similarities of PbZfp functions to functions of mammalian PRDM9, also a C 2 H 2 ZnF protein with histone 3 lysine 4 (H3K4) methyltransferase activity. These functions include the major role played by the latter in binding recombination hotspots in the genome during meiosis and trimethylation of the associated histones and subsequent chromatin recruitment of topoisomerase-like Spo11 to catalyze DNA DSB formation and DMC1/Rad51-mediated DNA repair and homologous recombination. IMPORTANCE Malaria parasites are haploid throughout their life cycle except for a brief time period when zygotes are produced as a result of fertilization between male and female gametes during transmission through the mosquito vector. The reciprocal recombination events that follow zygote formation ensure orderly segregation of homologous chromosomes during meiosis, creating genetic diversity among offspring. Studies presented in the current manuscript identify a novel C2H2 ZnF-containing protein exhibiting multifunctional roles in parasite virulence, mosquito transmission, and homologous recombination during meiosis. Understanding the transmission biology of malaria will result in the identification of novel targets for transmission-blocking intervention approaches.

Nuclear Lamins: Laminopathies and Their Role in Premature Ageing

2006 ◽  
Vol 86 (3) ◽  
pp. 967-1008 ◽  
Author(s):  
J. L. V. Broers ◽  
F. C. S. Ramaekers ◽  
G. Bonne ◽  
R. Ben Yaou ◽  
C. J. Hutchison
Keyword(s):  
Transcriptional Control ◽  
Current Knowledge ◽  
Gene Mutations ◽  
Muscular Diseases ◽  
Nuclear Lamins ◽  
Premature Ageing ◽  
The Family ◽  
Associated Proteins ◽  
Cellular Ageing ◽  
And Function

It has been demonstrated that nuclear lamins are important proteins in maintaining cellular as well as nuclear integrity, and in maintaining chromatin organization in the nucleus. Moreover, there is growing evidence that lamins play a prominent role in transcriptional control. The family of laminopathies is a fast-growing group of diseases caused by abnormalities in the structure or processing of the lamin A/C ( LMNA) gene. Mutations or incorrect processing cause more than a dozen different inherited diseases, ranging from striated muscular diseases, via fat- and peripheral nerve cell diseases, to progeria. This broad spectrum of diseases can only be explained if the responsible A-type lamin proteins perform multiple functions in normal cells. This review gives an overview of current knowledge on lamin structure and function and all known diseases associated with LMNA abnormalities. Based on the knowledge of the different functions of A-type lamins and associated proteins, explanations for the observed phenotypes are postulated. It is concluded that lamins seem to be key players in, among others, controlling the process of cellular ageing, since disturbance in lamin protein structure gives rise to several forms of premature ageing.

scholarly journals How Does SUMO Participate in Spindle Organization?

Cells ◽  
2019 ◽  
Vol 8 (8) ◽  
pp. 801
Author(s):  
Abrieu ◽  
Liakopoulos
Keyword(s):  
Dna Repair ◽  
Protein Assemblies ◽  
Cellular Mechanisms ◽  
Future Directions ◽  
Kinetochore Assembly ◽  
Associated Proteins ◽  
Long Time ◽  
And Function ◽  
Dependent Processes

The ubiquitin-like protein SUMO is a regulator involved in most cellular mechanisms. Recent studies have discovered new modes of function for this protein. Of particular interest is the ability of SUMO to organize proteins in larger assemblies, as well as the role of SUMO-dependent ubiquitylation in their disassembly. These mechanisms have been largely described in the context of DNA repair, transcriptional regulation, or signaling, while much less is known on how SUMO facilitates organization of microtubule-dependent processes during mitosis. Remarkably however, SUMO has been known for a long time to modify kinetochore proteins, while more recently, extensive proteomic screens have identified a large number of microtubule- and spindle-associated proteins that are SUMOylated. The aim of this review is to focus on the possible role of SUMOylation in organization of the spindle and kinetochore complexes. We summarize mitotic and microtubule/spindle-associated proteins that have been identified as SUMO conjugates and present examples regarding their regulation by SUMO. Moreover, we discuss the possible contribution of SUMOylation in organization of larger protein assemblies on the spindle, as well as the role of SUMO-targeted ubiquitylation in control of kinetochore assembly and function. Finally, we propose future directions regarding the study of SUMOylation in regulation of spindle organization and examine the potential of SUMO and SUMO-mediated degradation as target for antimitotic-based therapies.

scholarly journals Exploring the Structures and Functions of Macromolecular SLX4-Nuclease Complexes in Genome Stability

2021 ◽  
Vol 12 ◽  
Author(s):  
Brandon J. Payliss ◽  
Ayushi Patel ◽  
Anneka C. Sheppard ◽  
Haley D. M. Wyatt
Keyword(s):  
Dna Repair ◽  
Homologous Recombination ◽  
Genome Stability ◽  
Genome Instability ◽  
Strand Break ◽  
Biochemical Properties ◽  
Strand Breaks ◽  
Dna Double Strand Break ◽  
Recent Developments ◽  
And Function

All organisms depend on the ability of cells to accurately duplicate and segregate DNA into progeny. However, DNA is frequently damaged by factors in the environment and from within cells. One of the most dangerous lesions is a DNA double-strand break. Unrepaired breaks are a major driving force for genome instability. Cells contain sophisticated DNA repair networks to counteract the harmful effects of genotoxic agents, thus safeguarding genome integrity. Homologous recombination is a high-fidelity, template-dependent DNA repair pathway essential for the accurate repair of DNA nicks, gaps and double-strand breaks. Accurate homologous recombination depends on the ability of cells to remove branched DNA structures that form during repair, which is achieved through the opposing actions of helicases and structure-selective endonucleases. This review focuses on a structure-selective endonuclease called SLX1-SLX4 and the macromolecular endonuclease complexes that assemble on the SLX4 scaffold. First, we discuss recent developments that illuminate the structure and biochemical properties of this somewhat atypical structure-selective endonuclease. We then summarize the multifaceted roles that are fulfilled by human SLX1-SLX4 and its associated endonucleases in homologous recombination and genome stability. Finally, we discuss recent work on SLX4-binding proteins that may represent integral components of these macromolecular nuclease complexes, emphasizing the structure and function of a protein called SLX4IP.

The Smc5/6 Complex: New and Old Functions of the Enigmatic Long-Distance Relative

2018 ◽  
Vol 52 (1) ◽  
pp. 89-107 ◽  
Author(s):  
Luis Aragón
Keyword(s):  
Dna Repair ◽  
Genome Stability ◽  
Current Knowledge ◽  
Multiple Roles ◽  
Long Distance ◽  
Comprehensive Overview ◽  
The Stability ◽  
New Research ◽  
And Function ◽  
Virus Genomes

Smc5 and Smc6, together with the kleisin Nse4, form the heart of the enigmatic and poorly understood Smc5/6 complex, which is frequently viewed as a cousin of cohesin and condensin with functions in DNA repair. As novel functions for cohesin and condensin complexes in the organization of long-range chromatin architecture have recently emerged, new unsuspected roles for Smc5/6 have also surfaced. Here, I aim to provide a comprehensive overview of our current knowledge of the Smc5/6 complex, including its long-established function in genome stability, its multiple roles in DNA repair, and its recently discovered connection to the transcription inhibition of hepatitis B virus genomes. In addition, I summarize new research that is beginning to tease out the molecular details of Smc5/6 structure and function, knowledge that will illuminate the nuclear activities of Smc5/6 in the stability and dynamics of eukaryotic genomes.

scholarly journals Role of cytochrome c oxidase nuclear-encoded subunits in health and disease

2020 ◽  
pp. 947-965
Author(s):  
K Čunátová ◽  
D Pajuelo Reguera ◽  
J Houštěk ◽  
T Mráček ◽  
P Pecina
Keyword(s):  
Electron Transport ◽  
Cytochrome C ◽  
Cytochrome C Oxidase ◽  
Mammalian Cells ◽  
Current Knowledge ◽  
Fine Tuning ◽  
Transport Chain ◽  
Associated Proteins ◽  
And Function ◽  
Structural Levels

Cytochrome c oxidase (COX), the terminal enzyme of mitochondrial electron transport chain, couples electron transport to oxygen with generation of proton gradient indispensable for the production of vast majority of ATP molecules in mammalian cells. The review summarizes current knowledge of COX structure and function of nuclear-encoded COX subunits, which may modulate enzyme activity according to various conditions. Moreover, some nuclear-encoded subunits posess tissue-specific and development-specific isoforms, possibly enabling fine-tuning of COX function in individual tissues. The importance of nuclear-encoded subunits is emphasized by recently discovered pathogenic mutations in patients with severe mitopathies. In addition, proteins substoichiometrically associated with COX were found to contribute to COX activity regulation and stabilization of the respiratory supercomplexes. Based on the summarized data, a model of three levels of quaternary COX structure is postulated. Individual structural levels correspond to subunits of the i) catalytic center, ii) nuclear-encoded stoichiometric subunits and iii) associated proteins, which may constitute several forms of COX with varying composition and differentially regulated function.

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