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Yanbin Zhang - One of the best experts on this subject based on the ideXlab platform.
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impeding the single strand annealing pathway of dna double strand break repair by withaferin a mediated fanca degradation
DNA Repair, 2019Co-Authors: Guanying Wang, Anna Palovcak, Ralf Landgraf, Fenghua Yuan, Yan Li, Yanbin ZhangAbstract:Abstract FANCA is a key player in the canonical Fanconi anemia (FA) repair pathway. We have recently shown that FANCA also plays an important role in the single-strand annealing sub-pathway (SSA) of DNA double-strand break (DSB) repair by biochemically catalyzing single-strand annealing. Here, we report that a steroidal lactone withaferin A (WA) specifically impedes SSA repair by promoting FANCA downregulation at a sub-micromolar concentration range. We find that WA causes FANCA downregulation post-translationally in a proteasome-dependent manner. This WA-mediated downregulation is achieved through HSP90 inhibition and disruption of the FANCA-HSP90 interaction. WA-mediated FANCA degradation significantly reduces cellular SSA repair, abolishes FANCD2 monoubiquitination, elevates sensitivity to mitomycin C, and results in accumulation of DSBs. Importantly, the WA-induced defect in SSA repair is highly dependent on the absence of FANCA protein and overexpression of exogenous WT-FANCA protein in WA-treated cells significantly complements the repair defect.
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fanca promotes dna double strand break repair by catalyzing single strand annealing and strand exchange
Molecular Cell, 2018Co-Authors: Anaid Benitez, Anna Palovcak, Kevin An, Kevin Zheng, Guanying Wang, Fenghua Yuan, Alexander V Mazin, Jaewon Moon, Yanbin ZhangAbstract:Summary FANCA is a component of the Fanconi anemia (FA) core complex that activates DNA interstrand crosslink repair by monoubiquitination of FANCD2. Here, we report that purified FANCA protein catalyzes bidirectional single-strand annealing (SA) and strand exchange (SE) at a level comparable to RAD52, while a disease-causing FANCA mutant, F1263Δ, is defective in both activities. FANCG, which directly interacts with FANCA, dramatically stimulates its SA and SE activities. Alternatively, FANCB, which does not directly interact with FANCA, does not stimulate this activity. Importantly, five other patient-derived FANCA mutants also exhibit deficient SA and SE, suggesting that the biochemical activities of FANCA are relevant to the etiology of FA. A cell-based DNA double-strand break (DSB) repair assay demonstrates that FANCA plays a direct role in the single-strand annealing sub-pathway (SSA) of DSB repair by catalyzing SA, and this role is independent of the canonical FA pathway and RAD52.
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abstract 1286 fanca binds to nucleic acids and stimulates endonuclease activity of fen1
Cancer Research, 2013Co-Authors: Liangyue Qian, Xinliang Zhao, Gennaro Durso, Paola Rodrigueztello, Fenghua Yuan, Chaitanya Jain, Limin Song, Yanbin ZhangAbstract:Fanconi anemia is a rare autosomal recessive or X-linked genetic disease characterized by progressive bone marrow failure, various developmental anomalies, and cancer predisposition. Fanconi anemia complementation group A (FANCA) gene is one of the 15 disease-causing genes and has been found to be mutated in ∼60% of Fanconi anemia patients. Except for its constituent role in the ubiquitin ligase of the Fanconi anemia core complex, no other biochemical activity has been identified thus far. Using purified protein, we observed that human FANCA has intrinsic affinity to nucleic acids. FANCA binds to both single-stranded and double-stranded DNA; however, its affinity to single-stranded DNA is dramatically higher. FANCA also binds to RNA with an intriguingly higher affinity than its DNA counterpart. A patient-derived FANCA truncation mutant, Q772X, has diminished affinity to both DNA and RNA. On the contrary, the complementing C-terminal fragment of Q772X, C772-1455, retains the differentiated nucleic acids binding activity (RNA>ssDNA>dsDNA), indicating that the nucleic acids binding domain of FANCA is primarily located at its C-terminus. Using DNA and RNA ladders, we determined that the minimum numbers of nucleotides required for FANCA recognition are ∼30 for both DNA and RNA. By testing the affinity between FANCA and a variety of DNA structures, we found that a 5’ flap or tail on DNA facilitates its interaction with FANCA. In addition, we observed that FANCA greatly stimulates the endonuclease activity of flap endonuclease 1 (FEN1), which processes 5’ flap structures. Our study reported that purified human FANCA binds to nucleic acids with strong preference for single-stranded forms. Our finding suggests that FANCA FANCA may participate in maintenance of replication forks by regulating removal of Okazaki fragment during maturation of lagging strand replication. Citation Format: Liangyue Qian, Fenghua Yuan, Paola Rodriguez-Tello, Xinliang Zhao, Limin Song, Gennaro D9Urso, Chaitanya Jain, Yanbin Zhang. FANCA binds to nucleic acids and stimulates endonuclease activity of FEN1. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 1286. doi:10.1158/1538-7445.AM2013-1286
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fanconi anemia complementation group a fanca protein has intrinsic affinity for nucleic acids with preference for single stranded forms
Journal of Biological Chemistry, 2012Co-Authors: Fenghua Yuan, Liangyue Qian, Xinliang Zhao, Gennaro Durso, Chaitanya Jain, Limin Song, Yanbin ZhangAbstract:Abstract The Fanconi anemia complementation group A (FANCA) gene is one of 15 disease-causing genes and has been found to be mutated in ∼60% of Fanconi anemia patients. Using purified protein, we report that human FANCA has intrinsic affinity for nucleic acids. FANCA binds to both single-stranded (ssDNA) and double-stranded (dsDNA) DNAs; however, its affinity for ssDNA is significantly higher than for dsDNA in an electrophoretic mobility shift assay. FANCA also binds to RNA with an intriguingly higher affinity than its DNA counterpart. FANCA requires a certain length of nucleic acids for optimal binding. Using DNA and RNA ladders, we determined that the minimum number of nucleotides required for FANCA recognition is ∼30 for both DNA and RNA. By testing the affinity between FANCA and a variety of DNA structures, we found that a 5′-flap or 5′-tail on DNA facilitates its interaction with FANCA. A patient-derived FANCA truncation mutant (Q772X) has diminished affinity for both DNA and RNA. In contrast, the complementing C-terminal fragment of Q772X, C772–1455, retains the differentiated nucleic acid-binding activity (RNA > ssDNA > dsDNA), indicating that the nucleic acid-binding domain of FANCA is located primarily at its C terminus, where most disease-causing mutations are found.
Hagop Youssoufian - One of the best experts on this subject based on the ideXlab platform.
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functional analysis of the putative peroxidase domain of fanca the fanconi anemia complementation group a protein
Molecular Genetics and Metabolism, 2001Co-Authors: Hagop YoussoufianAbstract:Abstract Fanconi anemia (FA) is an autosomal recessive disorder manifested by chromosomal breakage, birth defects, and susceptibility to bone marrow failure and cancer. At least seven complementation groups have been identified, and the genes defective in four groups have been cloned. The most common subtype is complementation group A. Although the normal functions of the gene products defective in FA cells are not completely understood, a clue to the function of the FA group A gene product (FANCA) was provided by the detection of limited homology in the amino terminal region to a class of heme peroxidases. We evaluated this hypothesis by mutagenesis and functional complementation studies. We substituted alanine residues for the most conserved FANCA residues in the putative peroxidase domain and tested their effects on known biochemical and cellular functions of FANCA. While the substitution mutants were comparable to wild-type FANCA with regard to their stability, subcellular localization, and interaction with FANCG, only the Trp 183 -to-Ala substitution (W183A) abolished the ability of FANCA to complement the sensitivity of FA group A cells to mitomycin C. By contrast, TUNEL assays for apoptosis after exposure to H 2 O 2 showed no differences between parental FA group A cells, cells complemented with wild-type FANCA, and cells complemented with the W183A of FANCA. Moreover, semiquantitative RT-PCR analysis for the expression of the peroxide-sensitive heme oxygenase gene showed appropriate induction after H 2 O 2 exposure. Thus, W183A appears to be essential for the in vivo activity of FANCA in a manner independent of its interaction with FANCG. Moreover, neither wild-type FANCA nor the W183A mutation appears to alter the peroxide-induced apoptosisor peroxide-sensing ability of FA group A cells.
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Investigation of Fanconi anemia protein interactions by yeast two-hybrid analysis.
Biochemical and Biophysical Research Communications, 2000Co-Authors: Pia A. J. Huber, Hagop Youssoufian, Annette L. Medhurst, Christopher G. MathewAbstract:Abstract Fanconi anemia is a chromosomal breakage disorder with eight complementation groups (A–H), and three genes ( FANCA, FANCC, and FANCG ) have been identified. Initial investigations of the interaction between FANCA and FANCC, principally by co-immunoprecipitation, have proved controversial. We used the yeast two-hybrid assay to test for interactions of the FANCA, FANCC, and FANCG proteins. No activation of the reporter gene was observed in yeast co-expressing FANCA and FANCC as hybrid proteins, suggesting that FANCA does not directly interact with FANCC. However, a high level of activation was found when FANCA was co-expressed with FANCG, indicating strong, direct interaction between these proteins. Both FANCA and FANCG show weak but consistent interaction with themselves, suggesting that their function may involve dimerisation. The site of interaction of FANCG with FANCA was investigated by analysis of 12 mutant fragments of FANCG. Although both N- and C-terminal fragments did interact, binding to FANCA was drastically reduced, suggesting that more than one region of the FANCG protein is required for proper interaction with FANCA.
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resistance to mitomycin c requires direct interaction between the fanconi anemia proteins fanca and fancg in the nucleus through an arginine rich domain
Journal of Biological Chemistry, 1999Co-Authors: Frank A E Kruyt, Fadi Abouzahr, Hagop YoussoufianAbstract:Abstract Fanconi anemia (FA) is a genetically heterogeneous disorder characterized by bone marrow failure, birth defects, and chromosomal instability. Because FA cells are sensitive to mitomycin C (MMC), FA gene products could be involved in cellular defense mechanisms. The FANCA and FANCG proteins deficient in FA groups A and G interact directly with each other. We have localized the mutual interaction domains of these proteins to amino acids 18–29 of FANCA and to two noncontiguous carboxyl-terminal domains of FANCG encompassing amino acids 400–475 and 585–622. Site-directed mutagenesis of FANCA residues 18–29 revealed a novel arginine-rich interaction domain (RRRAWAELLAG). By alanine mutagenesis, Arg1, Arg2, and Leu8 but not Arg3, Trp5, and Glu7 appeared to be critical for binding to FANCG. Similar immunolocalization for FANCA and FANCG suggested that these proteins interact in vivo. Moreover, targeting of FANCA to the nucleus or the cytoplasm with nuclear localization and nuclear export signals, respectively, showed concordance between the localization patterns of FANCA and FANCG. The complementation function of FANCA was abolished by mutations in its FANCG-binding domain. Conversely, stable expression of FANCA mutants encoding intact FANCG interaction domains induced hypersensitivity to MMC in HeLa cells. These results demonstrate that FANCA-FANCG complexes are required for cellular resistance to MMC. Because the FANCC protein deficient in FA group C works within the cytoplasm, we suggest that FANCC and the FANCA-FANCG complexes suppress MMC cytotoxicity within distinct cellular compartments.
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expression of the fanconi anemia group a gene fanca during mouse embryogenesis
Blood, 1999Co-Authors: Radwan Abuissa, Gregor Eichele, Hagop YoussoufianAbstract:About 80% of all cases of Fanconi anemia (FA) can be accounted for by complementation groups A and C. To understand the relationship between these groups, we analyzed the expression pattern of the mouse FA group-A gene ( Fanca ) during embryogenesis and compared it with the known pattern of the group-C gene ( Fancc ). Northern analysis of RNA from mouse embryos at embryonic days 7, 11, 15, and 17 showed a predominant 4.5 kb band in all stages. By in situ hybridization, Fanca transcripts were found in the whisker follicles, teeth, brain, retina, kidney, liver, and limbs. There was also stage-specific variation in Fanca expression, particularly within the developing whiskers and the brain. Some tissues known to express Fancc (eg, gut) failed to show Fanca expression. These observations show that (1) Fanca is under both tissue- and stage-specific regulation in several tissues; (2) the expression pattern of Fanca is consistent with the phenotype of the human disease; and (3) Fanca expression is not necessarily coupled to that of Fancc . The presence of distinct tissue targets for FA genes suggests that some of the variability in the clinical phenotype can be attributed to the complementation group assignment.
Manuel A. Constenla - One of the best experts on this subject based on the ideXlab platform.
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Flavonoid and other constituents of Bauhinia Manca
Phytochemistry, 2001Co-Authors: Hans Achenbach, Markus Stöcker, Manuel A. ConstenlaAbstract:Abstract Phytochemical analysis of the stem of Bauhinia Manca yielded 63 compounds, among them six new natural products.
Fenghua Yuan - One of the best experts on this subject based on the ideXlab platform.
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impeding the single strand annealing pathway of dna double strand break repair by withaferin a mediated fanca degradation
DNA Repair, 2019Co-Authors: Guanying Wang, Anna Palovcak, Ralf Landgraf, Fenghua Yuan, Yan Li, Yanbin ZhangAbstract:Abstract FANCA is a key player in the canonical Fanconi anemia (FA) repair pathway. We have recently shown that FANCA also plays an important role in the single-strand annealing sub-pathway (SSA) of DNA double-strand break (DSB) repair by biochemically catalyzing single-strand annealing. Here, we report that a steroidal lactone withaferin A (WA) specifically impedes SSA repair by promoting FANCA downregulation at a sub-micromolar concentration range. We find that WA causes FANCA downregulation post-translationally in a proteasome-dependent manner. This WA-mediated downregulation is achieved through HSP90 inhibition and disruption of the FANCA-HSP90 interaction. WA-mediated FANCA degradation significantly reduces cellular SSA repair, abolishes FANCD2 monoubiquitination, elevates sensitivity to mitomycin C, and results in accumulation of DSBs. Importantly, the WA-induced defect in SSA repair is highly dependent on the absence of FANCA protein and overexpression of exogenous WT-FANCA protein in WA-treated cells significantly complements the repair defect.
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fanca promotes dna double strand break repair by catalyzing single strand annealing and strand exchange
Molecular Cell, 2018Co-Authors: Anaid Benitez, Anna Palovcak, Kevin An, Kevin Zheng, Guanying Wang, Fenghua Yuan, Alexander V Mazin, Jaewon Moon, Yanbin ZhangAbstract:Summary FANCA is a component of the Fanconi anemia (FA) core complex that activates DNA interstrand crosslink repair by monoubiquitination of FANCD2. Here, we report that purified FANCA protein catalyzes bidirectional single-strand annealing (SA) and strand exchange (SE) at a level comparable to RAD52, while a disease-causing FANCA mutant, F1263Δ, is defective in both activities. FANCG, which directly interacts with FANCA, dramatically stimulates its SA and SE activities. Alternatively, FANCB, which does not directly interact with FANCA, does not stimulate this activity. Importantly, five other patient-derived FANCA mutants also exhibit deficient SA and SE, suggesting that the biochemical activities of FANCA are relevant to the etiology of FA. A cell-based DNA double-strand break (DSB) repair assay demonstrates that FANCA plays a direct role in the single-strand annealing sub-pathway (SSA) of DSB repair by catalyzing SA, and this role is independent of the canonical FA pathway and RAD52.
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abstract 1286 fanca binds to nucleic acids and stimulates endonuclease activity of fen1
Cancer Research, 2013Co-Authors: Liangyue Qian, Xinliang Zhao, Gennaro Durso, Paola Rodrigueztello, Fenghua Yuan, Chaitanya Jain, Limin Song, Yanbin ZhangAbstract:Fanconi anemia is a rare autosomal recessive or X-linked genetic disease characterized by progressive bone marrow failure, various developmental anomalies, and cancer predisposition. Fanconi anemia complementation group A (FANCA) gene is one of the 15 disease-causing genes and has been found to be mutated in ∼60% of Fanconi anemia patients. Except for its constituent role in the ubiquitin ligase of the Fanconi anemia core complex, no other biochemical activity has been identified thus far. Using purified protein, we observed that human FANCA has intrinsic affinity to nucleic acids. FANCA binds to both single-stranded and double-stranded DNA; however, its affinity to single-stranded DNA is dramatically higher. FANCA also binds to RNA with an intriguingly higher affinity than its DNA counterpart. A patient-derived FANCA truncation mutant, Q772X, has diminished affinity to both DNA and RNA. On the contrary, the complementing C-terminal fragment of Q772X, C772-1455, retains the differentiated nucleic acids binding activity (RNA>ssDNA>dsDNA), indicating that the nucleic acids binding domain of FANCA is primarily located at its C-terminus. Using DNA and RNA ladders, we determined that the minimum numbers of nucleotides required for FANCA recognition are ∼30 for both DNA and RNA. By testing the affinity between FANCA and a variety of DNA structures, we found that a 5’ flap or tail on DNA facilitates its interaction with FANCA. In addition, we observed that FANCA greatly stimulates the endonuclease activity of flap endonuclease 1 (FEN1), which processes 5’ flap structures. Our study reported that purified human FANCA binds to nucleic acids with strong preference for single-stranded forms. Our finding suggests that FANCA FANCA may participate in maintenance of replication forks by regulating removal of Okazaki fragment during maturation of lagging strand replication. Citation Format: Liangyue Qian, Fenghua Yuan, Paola Rodriguez-Tello, Xinliang Zhao, Limin Song, Gennaro D9Urso, Chaitanya Jain, Yanbin Zhang. FANCA binds to nucleic acids and stimulates endonuclease activity of FEN1. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 1286. doi:10.1158/1538-7445.AM2013-1286
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fanconi anemia complementation group a fanca protein has intrinsic affinity for nucleic acids with preference for single stranded forms
Journal of Biological Chemistry, 2012Co-Authors: Fenghua Yuan, Liangyue Qian, Xinliang Zhao, Gennaro Durso, Chaitanya Jain, Limin Song, Yanbin ZhangAbstract:Abstract The Fanconi anemia complementation group A (FANCA) gene is one of 15 disease-causing genes and has been found to be mutated in ∼60% of Fanconi anemia patients. Using purified protein, we report that human FANCA has intrinsic affinity for nucleic acids. FANCA binds to both single-stranded (ssDNA) and double-stranded (dsDNA) DNAs; however, its affinity for ssDNA is significantly higher than for dsDNA in an electrophoretic mobility shift assay. FANCA also binds to RNA with an intriguingly higher affinity than its DNA counterpart. FANCA requires a certain length of nucleic acids for optimal binding. Using DNA and RNA ladders, we determined that the minimum number of nucleotides required for FANCA recognition is ∼30 for both DNA and RNA. By testing the affinity between FANCA and a variety of DNA structures, we found that a 5′-flap or 5′-tail on DNA facilitates its interaction with FANCA. A patient-derived FANCA truncation mutant (Q772X) has diminished affinity for both DNA and RNA. In contrast, the complementing C-terminal fragment of Q772X, C772–1455, retains the differentiated nucleic acid-binding activity (RNA > ssDNA > dsDNA), indicating that the nucleic acid-binding domain of FANCA is located primarily at its C terminus, where most disease-causing mutations are found.
Carmen Moran Rodriguez - One of the best experts on this subject based on the ideXlab platform.
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el espacio del folklore en la princesa Manca de gustavo martin garzo
SIGLO XXI, 2012Co-Authors: Carmen Moran RodriguezAbstract:El articulo analiza la presencia de diversos motivos del folktale en una de las novelas menos conocidas, pero mas singulares, del escritor vallisoletano Gustavo Martin Garzo, La princesa Manca (1995). Para ello, se valora el peso que el acervo de los cuentos tradicionales ha tenido en la formacion del autor y su manera de entender la literatura. El propio Martin Garzo proporciona numerosos testimonios de ello en diversos articulos publicados en prensa periodica, conferencias, etc. A partir de estas consideraciones se analizan distintos componentes de La princesa Manca que remiten a motivos bien reconocibles del folktale, que permanecen de este modo vigentes en una obra contemporanea, aunque renovados en su formulacion y su sentido. folklore in literature, folktale, traditional storytelling, traditional storytelling in literature, folk motifs in literature. This article analyzes the presence of various folktale motifs in one of the lesserknown, but unique novels, of the Valladolid writer Gustavo Martin Garzo, La princesa Manca (1995). To do this, this article assesses the weighty impact of traditional folk tales on the formation of the author and his understanding of literature. Garzo Martin himself provides numerous examples of such an influence in a variety of articles published in periodicals, conferences, etc. Given this as its starting point, various aspects of La princesa Manca are discussed with reference to recognizable folktale motifs that remain current in a contemporary work that updates them with new formulations and meaning.
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el espacio del folklore en la princesa Manca de gustavo martin garzo
Siglo XXI literatura y cultura españolas: revista de la Cátedra Miguel Delibes, 2010Co-Authors: Carmen Moran RodriguezAbstract:This article analyzes the presence of various folktale motifs in one of the lesserknown, but unique novels, of the Valladolid writer Gustavo Martin Garzo, La princesa Manca (1995). To do this, this article assesses the weighty impact of traditional folk tales on the formation of the author and his understanding of literature. Garzo Martin himself provides numerous examples of such an influence in a variety of articles published in periodicals, conferences, etc. Given this as its starting point, various aspects of La princesa Manca are discussed with reference to recognizable folktale motifs that remain current in a contemporary work that updates them with new formulations and meaning.