The Experts below are selected from a list of 2772 Experts worldwide ranked by ideXlab platform
Jacob G. Robison - One of the best experts on this subject based on the ideXlab platform.
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cell cycle and proteasome dependent formation of etoposide induced replication protein a rpa or mre11 rad50 nbs1 MRN Complex repair foci
Cell Cycle, 2007Co-Authors: Jacob G. Robison, Kathleen Dixon, John J. BisslerAbstract:In response to DNA damage, cells activate a Complex protein network designed to sustain genomic integrity. Many of the proteins involved in the network form discrete repair foci, the composition of which is determined by the specific type of damage. Replication protein A (RPA) and the Mre11/Rad50/Nbs1 (MRN) Complex both participate in foci and co-localize at certain types of lesions. Following etoposide (ETOP) treatment, cells form foci containing either RPA or the MRN Complex, but not both. To investigate this preferential foci formation, we used cell cycle synchronization experimentation. We demonstrate that cells in S phase contain RPA foci but lack phospho-Nbs1 foci. This is consistent with RPA’s role in homologous recombination repair of DNA double-strand breaks (DSBs), the predominant form of repair during S phase. Cells synchronized at G0/G1 phase contain phospho-Nbs1 foci, consistent with the MRN Complex involvement in non-homologous end joining, the predominant form of repair in G1 phase. Treatme...
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Cell cycle-and proteasome-dependent formation of etoposide-induced replication protein A (RPA) or Mre11/Rad50/Nbs1 (MRN) Complex repair foci
Cell cycle (Georgetown Tex.), 2007Co-Authors: Jacob G. Robison, Kathleen Dixon, John J. BisslerAbstract:In response to DNA damage, cells activate a Complex protein network designed to sustain genomic integrity. Many of the proteins involved in the network form discrete repair foci, the composition of which is determined by the specific type of damage. Replication protein A (RPA) and the Mre11/Rad50/Nbs1 (MRN) Complex both participate in foci and co-localize at certain types of lesions. Following etoposide (ETOP) treatment, cells form foci containing either RPA or the MRN Complex, but not both. To investigate this preferential foci formation, we used cell cycle synchronization experimentation. We demonstrate that cells in S phase contain RPA foci but lack phospho-Nbs1 foci. This is consistent with RPA’s role in homologous recombination repair of DNA double-strand breaks (DSBs), the predominant form of repair during S phase. Cells synchronized at G0/G1 phase contain phospho-Nbs1 foci, consistent with the MRN Complex involvement in non-homologous end joining, the predominant form of repair in G1 phase. Treatme...
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dna lesion specific co localization of the mre11 rad50 nbs1 MRN Complex and replication protein a rpa to repair foci
Journal of Biological Chemistry, 2005Co-Authors: Jacob G. Robison, Kathleen Dixon, John J. BisslerAbstract:The DNA damage response, triggered by DNA replication stress or DNA damage, involves the activation of DNA repair and cell cycle regulatory proteins including the MRN (Mre11, Rad50, and Nbs1) Complex and replication protein A (RPA). The induction of replication stress by hydroxyurea (HU) or DNA damage by camptothecin (CAMPT), etoposide (ETOP), or mitomycin C (MMC) led to the formation of nuclear foci containing phosphorylated Nbs1. HU and CAMPT treatment also led to the formation of RPA foci that co-localized with phospho-Nbs1 foci. After ETOP treatment, phospho-Nbs1 and RPA foci were detected but not within the same cell. MMC treatment resulted in phospho-Nbs1 foci formation in the absence of RPA foci. Consistent with the presence or absence of RPA foci, RPA hyperphosphorylation was present following HU, CAMPT, and ETOP treatment but absent following MMC treatment. The lack of co-localization of phospho-Nbs1 and RPA foci may be due to relatively shorter stretches of single-stranded DNA generated following ETOP and MMC treatment. These data suggest that, even though the MRN Complex and RPA can interact, their interaction may be limited to responses to specific types of lesions, particularly those that have longer stretches of single-stranded DNA. In addition, the consistent formation of phospho-Nbs1 foci in all of the treatment groups suggests that the MRN Complex may play a more universal role in the recognition and response to DNA lesions of all types, whereas the role of RPA may be limited to certain subsets of lesions.
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DNA Lesion-specific Co-localization of the Mre11/Rad50/Nbs1 (MRN) Complex and Replication Protein A (RPA) to Repair Foci
The Journal of biological chemistry, 2005Co-Authors: Jacob G. Robison, Kathleen Dixon, John J. BisslerAbstract:Abstract The DNA damage response, triggered by DNA replication stress or DNA damage, involves the activation of DNA repair and cell cycle regulatory proteins including the MRN (Mre11, Rad50, and Nbs1) Complex and replication protein A (RPA). The induction of replication stress by hydroxyurea (HU) or DNA damage by camptothecin (CAMPT), etoposide (ETOP), or mitomycin C (MMC) led to the formation of nuclear foci containing phosphorylated Nbs1. HU and CAMPT treatment also led to the formation of RPA foci that co-localized with phospho-Nbs1 foci. After ETOP treatment, phospho-Nbs1 and RPA foci were detected but not within the same cell. MMC treatment resulted in phospho-Nbs1 foci formation in the absence of RPA foci. Consistent with the presence or absence of RPA foci, RPA hyperphosphorylation was present following HU, CAMPT, and ETOP treatment but absent following MMC treatment. The lack of co-localization of phospho-Nbs1 and RPA foci may be due to relatively shorter stretches of single-stranded DNA generated following ETOP and MMC treatment. These data suggest that, even though the MRN Complex and RPA can interact, their interaction may be limited to responses to specific types of lesions, particularly those that have longer stretches of single-stranded DNA. In addition, the consistent formation of phospho-Nbs1 foci in all of the treatment groups suggests that the MRN Complex may play a more universal role in the recognition and response to DNA lesions of all types, whereas the role of RPA may be limited to certain subsets of lesions.
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Replication protein A and the Mre11.Rad50.Nbs1 Complex co-localize and interact at sites of stalled replication forks.
The Journal of biological chemistry, 2004Co-Authors: Jacob G. Robison, Kathleen Dixon, James Elliott, Gregory G. OakleyAbstract:Abstract In response to replicative stress, cells relocate and activate DNA repair and cell cycle arrest proteins such as replication protein A (RPA, a three subunit protein Complex required for DNA replication and DNA repair) and the MRN Complex (consisting of Mre11, Rad50, and Nbs1; involved in DNA double-strand break repair). There is increasing evidence that both of these Complexes play a central role in DNA damage recognition, activation of cell cycle checkpoints, and DNA repair pathways. Here we demonstrate that RPA and the MRN Complex co-localize to discrete foci and interact in response to DNA replication fork blockage induced by hydroxyurea (HU) or ultraviolet light (UV). Members of both RPA and the MRN Complexes become phosphorylated during S-phase and in response to replication fork blockage. Analysis of RPA and Mre11 in fractionated lysates (cytoplasmic/nucleoplasmic, chromatin-bound, and nuclear matrix fractions) showed increased hyperphosphorylated-RPA and phosphorylated-Mre11 in the chromatin-bound fractions. HU and UV treatment also led to co-localization of hyperphosphorylated RPA and Mre11 to discrete detergent-resistant nuclear foci. An interaction between RPA and Mre11 was demonstrated by co-immunoprecipitation of both protein Complexes with anti-Mre11, anti-Rad50, anti-NBS1, or anti-RPA antibodies. Phosphatase treatment with calf intestinal phosphatase or λ-phosphatase not only de-phosphorylated RPA and Mre11 but also abrogated the ability of RPA and the MRN Complex to co-immunoprecipitate. Together, these data demonstrate that RPA and the MRN Complex co-localize and interact after HU- or UV-induced replication stress and suggest that protein phosphorylation may play a role in this interaction.
John J. Bissler - One of the best experts on this subject based on the ideXlab platform.
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cell cycle and proteasome dependent formation of etoposide induced replication protein a rpa or mre11 rad50 nbs1 MRN Complex repair foci
Cell Cycle, 2007Co-Authors: Jacob G. Robison, Kathleen Dixon, John J. BisslerAbstract:In response to DNA damage, cells activate a Complex protein network designed to sustain genomic integrity. Many of the proteins involved in the network form discrete repair foci, the composition of which is determined by the specific type of damage. Replication protein A (RPA) and the Mre11/Rad50/Nbs1 (MRN) Complex both participate in foci and co-localize at certain types of lesions. Following etoposide (ETOP) treatment, cells form foci containing either RPA or the MRN Complex, but not both. To investigate this preferential foci formation, we used cell cycle synchronization experimentation. We demonstrate that cells in S phase contain RPA foci but lack phospho-Nbs1 foci. This is consistent with RPA’s role in homologous recombination repair of DNA double-strand breaks (DSBs), the predominant form of repair during S phase. Cells synchronized at G0/G1 phase contain phospho-Nbs1 foci, consistent with the MRN Complex involvement in non-homologous end joining, the predominant form of repair in G1 phase. Treatme...
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Cell cycle-and proteasome-dependent formation of etoposide-induced replication protein A (RPA) or Mre11/Rad50/Nbs1 (MRN) Complex repair foci
Cell cycle (Georgetown Tex.), 2007Co-Authors: Jacob G. Robison, Kathleen Dixon, John J. BisslerAbstract:In response to DNA damage, cells activate a Complex protein network designed to sustain genomic integrity. Many of the proteins involved in the network form discrete repair foci, the composition of which is determined by the specific type of damage. Replication protein A (RPA) and the Mre11/Rad50/Nbs1 (MRN) Complex both participate in foci and co-localize at certain types of lesions. Following etoposide (ETOP) treatment, cells form foci containing either RPA or the MRN Complex, but not both. To investigate this preferential foci formation, we used cell cycle synchronization experimentation. We demonstrate that cells in S phase contain RPA foci but lack phospho-Nbs1 foci. This is consistent with RPA’s role in homologous recombination repair of DNA double-strand breaks (DSBs), the predominant form of repair during S phase. Cells synchronized at G0/G1 phase contain phospho-Nbs1 foci, consistent with the MRN Complex involvement in non-homologous end joining, the predominant form of repair in G1 phase. Treatme...
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dna lesion specific co localization of the mre11 rad50 nbs1 MRN Complex and replication protein a rpa to repair foci
Journal of Biological Chemistry, 2005Co-Authors: Jacob G. Robison, Kathleen Dixon, John J. BisslerAbstract:The DNA damage response, triggered by DNA replication stress or DNA damage, involves the activation of DNA repair and cell cycle regulatory proteins including the MRN (Mre11, Rad50, and Nbs1) Complex and replication protein A (RPA). The induction of replication stress by hydroxyurea (HU) or DNA damage by camptothecin (CAMPT), etoposide (ETOP), or mitomycin C (MMC) led to the formation of nuclear foci containing phosphorylated Nbs1. HU and CAMPT treatment also led to the formation of RPA foci that co-localized with phospho-Nbs1 foci. After ETOP treatment, phospho-Nbs1 and RPA foci were detected but not within the same cell. MMC treatment resulted in phospho-Nbs1 foci formation in the absence of RPA foci. Consistent with the presence or absence of RPA foci, RPA hyperphosphorylation was present following HU, CAMPT, and ETOP treatment but absent following MMC treatment. The lack of co-localization of phospho-Nbs1 and RPA foci may be due to relatively shorter stretches of single-stranded DNA generated following ETOP and MMC treatment. These data suggest that, even though the MRN Complex and RPA can interact, their interaction may be limited to responses to specific types of lesions, particularly those that have longer stretches of single-stranded DNA. In addition, the consistent formation of phospho-Nbs1 foci in all of the treatment groups suggests that the MRN Complex may play a more universal role in the recognition and response to DNA lesions of all types, whereas the role of RPA may be limited to certain subsets of lesions.
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DNA Lesion-specific Co-localization of the Mre11/Rad50/Nbs1 (MRN) Complex and Replication Protein A (RPA) to Repair Foci
The Journal of biological chemistry, 2005Co-Authors: Jacob G. Robison, Kathleen Dixon, John J. BisslerAbstract:Abstract The DNA damage response, triggered by DNA replication stress or DNA damage, involves the activation of DNA repair and cell cycle regulatory proteins including the MRN (Mre11, Rad50, and Nbs1) Complex and replication protein A (RPA). The induction of replication stress by hydroxyurea (HU) or DNA damage by camptothecin (CAMPT), etoposide (ETOP), or mitomycin C (MMC) led to the formation of nuclear foci containing phosphorylated Nbs1. HU and CAMPT treatment also led to the formation of RPA foci that co-localized with phospho-Nbs1 foci. After ETOP treatment, phospho-Nbs1 and RPA foci were detected but not within the same cell. MMC treatment resulted in phospho-Nbs1 foci formation in the absence of RPA foci. Consistent with the presence or absence of RPA foci, RPA hyperphosphorylation was present following HU, CAMPT, and ETOP treatment but absent following MMC treatment. The lack of co-localization of phospho-Nbs1 and RPA foci may be due to relatively shorter stretches of single-stranded DNA generated following ETOP and MMC treatment. These data suggest that, even though the MRN Complex and RPA can interact, their interaction may be limited to responses to specific types of lesions, particularly those that have longer stretches of single-stranded DNA. In addition, the consistent formation of phospho-Nbs1 foci in all of the treatment groups suggests that the MRN Complex may play a more universal role in the recognition and response to DNA lesions of all types, whereas the role of RPA may be limited to certain subsets of lesions.
Kathleen Dixon - One of the best experts on this subject based on the ideXlab platform.
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cell cycle and proteasome dependent formation of etoposide induced replication protein a rpa or mre11 rad50 nbs1 MRN Complex repair foci
Cell Cycle, 2007Co-Authors: Jacob G. Robison, Kathleen Dixon, John J. BisslerAbstract:In response to DNA damage, cells activate a Complex protein network designed to sustain genomic integrity. Many of the proteins involved in the network form discrete repair foci, the composition of which is determined by the specific type of damage. Replication protein A (RPA) and the Mre11/Rad50/Nbs1 (MRN) Complex both participate in foci and co-localize at certain types of lesions. Following etoposide (ETOP) treatment, cells form foci containing either RPA or the MRN Complex, but not both. To investigate this preferential foci formation, we used cell cycle synchronization experimentation. We demonstrate that cells in S phase contain RPA foci but lack phospho-Nbs1 foci. This is consistent with RPA’s role in homologous recombination repair of DNA double-strand breaks (DSBs), the predominant form of repair during S phase. Cells synchronized at G0/G1 phase contain phospho-Nbs1 foci, consistent with the MRN Complex involvement in non-homologous end joining, the predominant form of repair in G1 phase. Treatme...
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Cell cycle-and proteasome-dependent formation of etoposide-induced replication protein A (RPA) or Mre11/Rad50/Nbs1 (MRN) Complex repair foci
Cell cycle (Georgetown Tex.), 2007Co-Authors: Jacob G. Robison, Kathleen Dixon, John J. BisslerAbstract:In response to DNA damage, cells activate a Complex protein network designed to sustain genomic integrity. Many of the proteins involved in the network form discrete repair foci, the composition of which is determined by the specific type of damage. Replication protein A (RPA) and the Mre11/Rad50/Nbs1 (MRN) Complex both participate in foci and co-localize at certain types of lesions. Following etoposide (ETOP) treatment, cells form foci containing either RPA or the MRN Complex, but not both. To investigate this preferential foci formation, we used cell cycle synchronization experimentation. We demonstrate that cells in S phase contain RPA foci but lack phospho-Nbs1 foci. This is consistent with RPA’s role in homologous recombination repair of DNA double-strand breaks (DSBs), the predominant form of repair during S phase. Cells synchronized at G0/G1 phase contain phospho-Nbs1 foci, consistent with the MRN Complex involvement in non-homologous end joining, the predominant form of repair in G1 phase. Treatme...
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dna lesion specific co localization of the mre11 rad50 nbs1 MRN Complex and replication protein a rpa to repair foci
Journal of Biological Chemistry, 2005Co-Authors: Jacob G. Robison, Kathleen Dixon, John J. BisslerAbstract:The DNA damage response, triggered by DNA replication stress or DNA damage, involves the activation of DNA repair and cell cycle regulatory proteins including the MRN (Mre11, Rad50, and Nbs1) Complex and replication protein A (RPA). The induction of replication stress by hydroxyurea (HU) or DNA damage by camptothecin (CAMPT), etoposide (ETOP), or mitomycin C (MMC) led to the formation of nuclear foci containing phosphorylated Nbs1. HU and CAMPT treatment also led to the formation of RPA foci that co-localized with phospho-Nbs1 foci. After ETOP treatment, phospho-Nbs1 and RPA foci were detected but not within the same cell. MMC treatment resulted in phospho-Nbs1 foci formation in the absence of RPA foci. Consistent with the presence or absence of RPA foci, RPA hyperphosphorylation was present following HU, CAMPT, and ETOP treatment but absent following MMC treatment. The lack of co-localization of phospho-Nbs1 and RPA foci may be due to relatively shorter stretches of single-stranded DNA generated following ETOP and MMC treatment. These data suggest that, even though the MRN Complex and RPA can interact, their interaction may be limited to responses to specific types of lesions, particularly those that have longer stretches of single-stranded DNA. In addition, the consistent formation of phospho-Nbs1 foci in all of the treatment groups suggests that the MRN Complex may play a more universal role in the recognition and response to DNA lesions of all types, whereas the role of RPA may be limited to certain subsets of lesions.
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DNA Lesion-specific Co-localization of the Mre11/Rad50/Nbs1 (MRN) Complex and Replication Protein A (RPA) to Repair Foci
The Journal of biological chemistry, 2005Co-Authors: Jacob G. Robison, Kathleen Dixon, John J. BisslerAbstract:Abstract The DNA damage response, triggered by DNA replication stress or DNA damage, involves the activation of DNA repair and cell cycle regulatory proteins including the MRN (Mre11, Rad50, and Nbs1) Complex and replication protein A (RPA). The induction of replication stress by hydroxyurea (HU) or DNA damage by camptothecin (CAMPT), etoposide (ETOP), or mitomycin C (MMC) led to the formation of nuclear foci containing phosphorylated Nbs1. HU and CAMPT treatment also led to the formation of RPA foci that co-localized with phospho-Nbs1 foci. After ETOP treatment, phospho-Nbs1 and RPA foci were detected but not within the same cell. MMC treatment resulted in phospho-Nbs1 foci formation in the absence of RPA foci. Consistent with the presence or absence of RPA foci, RPA hyperphosphorylation was present following HU, CAMPT, and ETOP treatment but absent following MMC treatment. The lack of co-localization of phospho-Nbs1 and RPA foci may be due to relatively shorter stretches of single-stranded DNA generated following ETOP and MMC treatment. These data suggest that, even though the MRN Complex and RPA can interact, their interaction may be limited to responses to specific types of lesions, particularly those that have longer stretches of single-stranded DNA. In addition, the consistent formation of phospho-Nbs1 foci in all of the treatment groups suggests that the MRN Complex may play a more universal role in the recognition and response to DNA lesions of all types, whereas the role of RPA may be limited to certain subsets of lesions.
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Replication protein A and the Mre11.Rad50.Nbs1 Complex co-localize and interact at sites of stalled replication forks.
The Journal of biological chemistry, 2004Co-Authors: Jacob G. Robison, Kathleen Dixon, James Elliott, Gregory G. OakleyAbstract:Abstract In response to replicative stress, cells relocate and activate DNA repair and cell cycle arrest proteins such as replication protein A (RPA, a three subunit protein Complex required for DNA replication and DNA repair) and the MRN Complex (consisting of Mre11, Rad50, and Nbs1; involved in DNA double-strand break repair). There is increasing evidence that both of these Complexes play a central role in DNA damage recognition, activation of cell cycle checkpoints, and DNA repair pathways. Here we demonstrate that RPA and the MRN Complex co-localize to discrete foci and interact in response to DNA replication fork blockage induced by hydroxyurea (HU) or ultraviolet light (UV). Members of both RPA and the MRN Complexes become phosphorylated during S-phase and in response to replication fork blockage. Analysis of RPA and Mre11 in fractionated lysates (cytoplasmic/nucleoplasmic, chromatin-bound, and nuclear matrix fractions) showed increased hyperphosphorylated-RPA and phosphorylated-Mre11 in the chromatin-bound fractions. HU and UV treatment also led to co-localization of hyperphosphorylated RPA and Mre11 to discrete detergent-resistant nuclear foci. An interaction between RPA and Mre11 was demonstrated by co-immunoprecipitation of both protein Complexes with anti-Mre11, anti-Rad50, anti-NBS1, or anti-RPA antibodies. Phosphatase treatment with calf intestinal phosphatase or λ-phosphatase not only de-phosphorylated RPA and Mre11 but also abrogated the ability of RPA and the MRN Complex to co-immunoprecipitate. Together, these data demonstrate that RPA and the MRN Complex co-localize and interact after HU- or UV-induced replication stress and suggest that protein phosphorylation may play a role in this interaction.
A. De Bustos - One of the best experts on this subject based on the ideXlab platform.
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The MRN Complex of wheat.
Czech Journal of Genetics and Plant Breeding, 2011Co-Authors: A. De Bustos, R. Pérez, Angeles Cuadrado, Nicolás JouveAbstract:The MRN Complex is formed by the interaction of the products of the Mre11, Rad50 and Nbs1 genes. This Complex plays a central role on repair of double-strand breaks (DSBs) and acts in a great number of cel - lular processes. In this study we have performed the analysis of the MRN Complex in diploid and polyploid species of wheat. The molecular characterization was carried out in the diploid T. monococcum (genome A) and Ae. tauschii (genome D) and in the tetraploid T. turgidum (genomes A and B). The results obtained showed that in all cases the genes presented the main characteristics previously described in other species. A modified FISH protocol was used to locate the Rad50, Mre11 and the Nbs1 genes on the homoeologous chromosomes 5, 2 and 1, respectively. Analysis of expression showed that the hexaploid T. aestivum was the species with the higher level of expression whereas the rest of the species analysed showed no relation with its ploidy. Also, quantification of the expression of each homoeologous gene in the polyploid species evidenced in some cases a process of silencing after polyploidization. The study of the interaction between the proteins demonstrated that the interaction of proteins was not restricted to each genome, detecting interaction between proteins belonging to different genomes.
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The Rad50 genes of diploid and polyploid wheat species. Analysis of homologue and homoeologue expression and interactions with Mre11
Theoretical and Applied Genetics, 2011Co-Authors: R. Pérez, A. Cuadrado, I. P. Chen, H. Puchta, N. Jouve, A. De BustosAbstract:The MRN Complex plays a central role in the DNA repair pathways of eukaryotic cells and takes part in many other processes, including cell cycle checkpoint signalling, meiosis, DNA replication and telomere maintenance. This Complex is formed by the interaction of the products of the Mre11 , Rad50 and Nbs1 genes. This paper reports the molecular characterization, expression and interactions of the Rad50 gene in several wheat species with different levels of ploidy. The homoeologous Rad50 wheat genes were found to show a high level of conservation. Most of the RAD50 domains and motifs previously described in other species were also present in wheat RAD50; these proteins are therefore likely to have similar functions. Interactions between the RAD50 wheat proteins and their MRE11 counterparts in the MRN Complex were observed. The level of expression of Rad50 in each of the species examined was determined and compared with those previously reported for the Mre11 genes. In some cases similar levels of expression were seen, as expected. The expression of the RAD50 homoeologous genes was assessed in two polyploid wheat species using quantitative PCR. In both cases, an overexpression of the Rad50B gene was detected. Although the results indicate the maintenance of function of these species’ three homoeologous Rad50 genes, the biased expression of Rad50B might indicate ongoing silencing of one or both other homoeologues in polyploid wheat. To assess the consequences of such silencing on the formation of the MRN Complex, the interactions between individual homoeologues of Rad50 and their genomic counterpart Mre11 genes were examined. The results indicate the inexistence of genomic specificity in the interactions between these genes. This would guarantee the formation of an MRN Complex in wheat.
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The Rad50 genes of diploid and polyploid wheat species. Analysis of homologue and homoeologue expression and interactions with Mre11
Theoretical and Applied Genetics, 2011Co-Authors: R. Pérez, A. Cuadrado, I. P. Chen, H. Puchta, N. Jouve, A. De BustosAbstract:The MRN Complex plays a central role in the DNA repair pathways of eukaryotic cells and takes part in many other processes, including cell cycle checkpoint signalling, meiosis, DNA replication and telomere maintenance. This Complex is formed by the interaction of the products of the Mre11 , Rad50 and Nbs1 genes. This paper reports the molecular characterization, expression and interactions of the Rad50 gene in several wheat species with different levels of ploidy. The homoeologous Rad50 wheat genes were found to show a high level of conservation. Most of the RAD50 domains and motifs previously described in other species were also present in wheat RAD50; these proteins are therefore likely to have similar functions. Interactions between the RAD50 wheat proteins and their MRE11 counterparts in the MRN Complex were observed. The level of expression of Rad50 in each of the species examined was determined and compared with those previously reported for the Mre11 genes. In some cases similar levels of expression were seen, as expected. The expression of the RAD50 homoeologous genes was assessed in two polyploid wheat species using quantitative PCR. In both cases, an overexpression of the Rad50B gene was detected. Although the results indicate the maintenance of function of these species’ three homoeologous Rad50 genes, the biased expression of Rad50B might indicate ongoing silencing of one or both other homoeologues in polyploid wheat. To assess the consequences of such silencing on the formation of the MRN Complex, the interactions between individual homoeologues of Rad50 and their genomic counterpart Mre11 genes were examined. The results indicate the inexistence of genomic specificity in the interactions between these genes. This would guarantee the formation of an MRN Complex in wheat.
Matthew D Weitzman - One of the best experts on this subject based on the ideXlab platform.
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the MRN Complex in double strand break repair and telomere maintenance
FEBS Letters, 2010Co-Authors: Brandon J Lamarche, Nicole I. Orazio, Matthew D WeitzmanAbstract:Genomes are subject to constant threat by damaging agents that generate DNA double-strand breaks (DSBs). The ends of linear chromosomes need to be protected from DNA damage recognition and end-joining, and this is achieved through protein–DNA Complexes known as telomeres. The Mre11–Rad50–Nbs1 (MRN) Complex plays important roles in detection and signaling of DSBs, as well as the repair pathways of homologous recombination (HR) and non-homologous end-joining (NHEJ). In addition, MRN associates with telomeres and contributes to their maintenance. Here, we provide an overview of MRN functions at DSBs, and examine its roles in telomere maintenance and dysfunction.
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The MRN Complex in double‐strand break repair and telomere maintenance
FEBS letters, 2010Co-Authors: Brandon J Lamarche, Nicole I. Orazio, Matthew D WeitzmanAbstract:Genomes are subject to constant threat by damaging agents that generate DNA double-strand breaks (DSBs). The ends of linear chromosomes need to be protected from DNA damage recognition and end-joining, and this is achieved through protein–DNA Complexes known as telomeres. The Mre11–Rad50–Nbs1 (MRN) Complex plays important roles in detection and signaling of DSBs, as well as the repair pathways of homologous recombination (HR) and non-homologous end-joining (NHEJ). In addition, MRN associates with telomeres and contributes to their maintenance. Here, we provide an overview of MRN functions at DSBs, and examine its roles in telomere maintenance and dysfunction.