The Experts below are selected from a list of 7524 Experts worldwide ranked by ideXlab platform
T. Nishimoto - One of the best experts on this subject based on the ideXlab platform.
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a mutant form of the Ran tc4 Protein disrupts nuclear function in xenopus laevis egg extracts by inhibiting the rcc1 Protein a regulator of chromosome condensation
The EMBO Journal, 1994Co-Authors: Mary Dasso, T Ohba, T. Seki, Yoshiaki Azuma, T. NishimotoAbstract:Abstract The Ran Protein is a small GTPase that has been implicated in a large number of nuclear processes including tRansport. RNA processing and cell cycle checkpoint control. A similar spectrum of nuclear activities has been shown to require RCC1, the guanine nucleotide exchange factor (GEF) for Ran. We have used the Xenopus laevis egg extract system and in vitro assays of purified Proteins to examine how Ran or RCC1 could be involved in these numerous processes. In these studies, we employed mutant Ran Proteins to perturb nuclear assembly and function. The addition of a bacterially expressed mutant form of Ran (T24N-Ran), which was predicted to be primarily in the GDP-bound state, profoundly disrupted nuclear assembly and DNA replication in extracts. We further examined the molecular mechanism by which T24N-Ran disrupts normal nuclear activity and found that T24N-Ran binds tightly to the RCC1 Protein within the extract, resulting in its inactivation as a GEF. The capacity of T24N-Ran-blocked interphase extracts to assemble nuclei from de-membRanated sperm chromatin and to replicate their DNA could be restored by supplementing the extract with excess RCC1 and thereby providing excess GEF activity. Conversely, nuclear assembly and DNA replication were both rescued in extracts lacking RCC1 by the addition of high levels of wild-type GTP-bound Ran Protein, indicating that RCC1 does not have an essential function beyond its role as a GEF in interphase Xenopus extracts.
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A mutant form of the Ran/TC4 Protein disrupts nuclear function in Xenopus laevis egg extracts by inhibiting the RCC1 Protein, a regulator of chromosome condensation.
The EMBO Journal, 1994Co-Authors: Mary Dasso, T Ohba, T. Seki, Yoshiaki Azuma, T. NishimotoAbstract:Abstract The Ran Protein is a small GTPase that has been implicated in a large number of nuclear processes including tRansport. RNA processing and cell cycle checkpoint control. A similar spectrum of nuclear activities has been shown to require RCC1, the guanine nucleotide exchange factor (GEF) for Ran. We have used the Xenopus laevis egg extract system and in vitro assays of purified Proteins to examine how Ran or RCC1 could be involved in these numerous processes. In these studies, we employed mutant Ran Proteins to perturb nuclear assembly and function. The addition of a bacterially expressed mutant form of Ran (T24N-Ran), which was predicted to be primarily in the GDP-bound state, profoundly disrupted nuclear assembly and DNA replication in extracts. We further examined the molecular mechanism by which T24N-Ran disrupts normal nuclear activity and found that T24N-Ran binds tightly to the RCC1 Protein within the extract, resulting in its inactivation as a GEF. The capacity of T24N-Ran-blocked interphase extracts to assemble nuclei from de-membRanated sperm chromatin and to replicate their DNA could be restored by supplementing the extract with excess RCC1 and thereby providing excess GEF activity. Conversely, nuclear assembly and DNA replication were both rescued in extracts lacking RCC1 by the addition of high levels of wild-type GTP-bound Ran Protein, indicating that RCC1 does not have an essential function beyond its role as a GEF in interphase Xenopus extracts.
Xiaobo Zhang - One of the best experts on this subject based on the ideXlab platform.
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Involvement of Ran in the regulation of phagocytosis against virus infection in S2 cells
Developmental and comparative immunology, 2013Co-Authors: Xiaobo ZhangAbstract:Phagocytosis plays important roles in innate and adaptive immunity in animals. Some small G Proteins are found to be related to phagocytosis. However, the Ran GTPase has not been intensively characterized in immunity. In this paper, the sequence analysis showed that the Ran was highly conserved in animals, suggesting that its function was preserved during animal evolution. The results showed that Ran was upregulated in S2 cells in response to DCV infection. It was further revealed that the antiviral phagocytosis could be mediated by Ran in S2 cells. By comparison with the early marker and late marker of phagosomes, the results showed that the Ran Protein played an essential role at the early stage of phagocytosis or throughout the entire phagocytic process. Therefore our findings enlarged our limited knowledge about the phagocytosis regulation by small G Proteins concerning to the nucleus.
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Effects of immunostimulants targeting Ran GTPase on phagocytosis against virus infection in shrimp
Fish & shellfish immunology, 2011Co-Authors: Zhe Zhao, Chunxia Jiang, Xiaobo ZhangAbstract:The global shrimp aquaculture has been consistently beset by diseases that cause severe losses in production. To fight various harmful pathogens, the enhanced shrimp immunity by immunostimulants would play key roles against the invading pathogens. In aquaculture, however, the target Proteins/genes which can be used for the screening of immunostimulants are very limited. Based on our previous study, in the present study, the shrimp Ran Protein, which was required in shrimp antiviral phagocytosis, was used as the target Protein to screen for immunostimulants. The GTPase activity assays showed that the IL-4 and lysophosphatidylcholine molecules could enhance the activity of Ran Protein, suggesting that the two molecules might function in phagocytosis. When the IL-4 and lysophosphatidylcholine were respectively injected into shrimp, the results indicated that the two molecules enhanced the hemocytic phagocytosis against white spot syndrome virus (WSSV), suggesting that they improved the activity of phagocytosis through the activation of the Ran Protein. It was evidenced that the enhancement of phagocytosis activity effectively inhibited the WSSV infection in shrimp, which further led to the decrease of mortalities of WSSV-infected shrimp. Therefore, our study presented a novel strategy for the screening of immunostimulants by using the key Proteins in immune responses of aquatic organisms as the target Proteins, which would be very helpful for the development of efficient approaches to prevent the aquatic organisms from pathogen infections.
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Feedback regulation of Ran gene expression by Ran Protein
Gene, 2011Co-Authors: Zhe Zhao, Jiajia Wang, Xiaobo ZhangAbstract:Ran, an abundant GTPase that is highly conserved in eukaryotes from yeast to human, has been implicated in many aspects of nuclear structure and function. Recently it is revealed that the Ran GTPase can regulate the hemocytic phagocytosis of shrimp by interaction with myosin. However the regulation of Ran gene expression remains unknown. In this study, the promoter of shrimp Ran gene was identified which contained a typical TATA box. The results showed that the shrimp Ran Protein was bound with the Ran promoter in Drosophila S2 cells. Based on luciferase assays, our study indicated that the tRanscription of Ran gene could be regulated by the interaction between the Ran promoter and the Ran Protein, suggesting the existence of a feedback regulation in Ran gene expression. Therefore our study presented a novel finding on the feedback regulation of gene tRanscription.
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Characterization of a ras-related nuclear Protein (Ran Protein) up-regulated in shrimp antiviral immunity.
Fish & shellfish immunology, 2007Co-Authors: Fang Han, Xiaobo ZhangAbstract:Abstract Diseases caused by viruses, especially white spot syndrome virus (WSSV), are the greatest challenge to worldwide shrimp aquaculture. Therefore, the innate immunity of shrimp has attracted extensive attentions these years. To date, however, no mechanism of immuno-related signal tRansduction pathway has been reported. In this investigation, an important signal tRansduction factor—Ran gene encoding ras-related nuclear Protein (Ran Protein) was characterized in shrimp. The shrimp Ran gene, without introns when compared with genomic DNA, was 645 bp in length. The GTP-binding assay showed that the Ran Protein had GTP-binding activity. The results of RT-PCR and Western blot indicated that the tRanscript and Protein of Ran were detected in every tissue of shrimp including hepatopancreas, haemolymph, gill, intestine, heart and muscle. In the WSSV-resistant and WSSV-infected shrimp at 4 h postinfection, the Ran gene was obviously up-regulated, indicating that it played a role in shrimp immunity against virus infection. This study, therefore, might provide a clue to elucidate shrimp innate immunity.
Mary Dasso - One of the best experts on this subject based on the ideXlab platform.
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a mutant form of the Ran tc4 Protein disrupts nuclear function in xenopus laevis egg extracts by inhibiting the rcc1 Protein a regulator of chromosome condensation
The EMBO Journal, 1994Co-Authors: Mary Dasso, T Ohba, T. Seki, Yoshiaki Azuma, T. NishimotoAbstract:Abstract The Ran Protein is a small GTPase that has been implicated in a large number of nuclear processes including tRansport. RNA processing and cell cycle checkpoint control. A similar spectrum of nuclear activities has been shown to require RCC1, the guanine nucleotide exchange factor (GEF) for Ran. We have used the Xenopus laevis egg extract system and in vitro assays of purified Proteins to examine how Ran or RCC1 could be involved in these numerous processes. In these studies, we employed mutant Ran Proteins to perturb nuclear assembly and function. The addition of a bacterially expressed mutant form of Ran (T24N-Ran), which was predicted to be primarily in the GDP-bound state, profoundly disrupted nuclear assembly and DNA replication in extracts. We further examined the molecular mechanism by which T24N-Ran disrupts normal nuclear activity and found that T24N-Ran binds tightly to the RCC1 Protein within the extract, resulting in its inactivation as a GEF. The capacity of T24N-Ran-blocked interphase extracts to assemble nuclei from de-membRanated sperm chromatin and to replicate their DNA could be restored by supplementing the extract with excess RCC1 and thereby providing excess GEF activity. Conversely, nuclear assembly and DNA replication were both rescued in extracts lacking RCC1 by the addition of high levels of wild-type GTP-bound Ran Protein, indicating that RCC1 does not have an essential function beyond its role as a GEF in interphase Xenopus extracts.
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A mutant form of the Ran/TC4 Protein disrupts nuclear function in Xenopus laevis egg extracts by inhibiting the RCC1 Protein, a regulator of chromosome condensation.
The EMBO Journal, 1994Co-Authors: Mary Dasso, T Ohba, T. Seki, Yoshiaki Azuma, T. NishimotoAbstract:Abstract The Ran Protein is a small GTPase that has been implicated in a large number of nuclear processes including tRansport. RNA processing and cell cycle checkpoint control. A similar spectrum of nuclear activities has been shown to require RCC1, the guanine nucleotide exchange factor (GEF) for Ran. We have used the Xenopus laevis egg extract system and in vitro assays of purified Proteins to examine how Ran or RCC1 could be involved in these numerous processes. In these studies, we employed mutant Ran Proteins to perturb nuclear assembly and function. The addition of a bacterially expressed mutant form of Ran (T24N-Ran), which was predicted to be primarily in the GDP-bound state, profoundly disrupted nuclear assembly and DNA replication in extracts. We further examined the molecular mechanism by which T24N-Ran disrupts normal nuclear activity and found that T24N-Ran binds tightly to the RCC1 Protein within the extract, resulting in its inactivation as a GEF. The capacity of T24N-Ran-blocked interphase extracts to assemble nuclei from de-membRanated sperm chromatin and to replicate their DNA could be restored by supplementing the extract with excess RCC1 and thereby providing excess GEF activity. Conversely, nuclear assembly and DNA replication were both rescued in extracts lacking RCC1 by the addition of high levels of wild-type GTP-bound Ran Protein, indicating that RCC1 does not have an essential function beyond its role as a GEF in interphase Xenopus extracts.
T Ohba - One of the best experts on this subject based on the ideXlab platform.
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a mutant form of the Ran tc4 Protein disrupts nuclear function in xenopus laevis egg extracts by inhibiting the rcc1 Protein a regulator of chromosome condensation
The EMBO Journal, 1994Co-Authors: Mary Dasso, T Ohba, T. Seki, Yoshiaki Azuma, T. NishimotoAbstract:Abstract The Ran Protein is a small GTPase that has been implicated in a large number of nuclear processes including tRansport. RNA processing and cell cycle checkpoint control. A similar spectrum of nuclear activities has been shown to require RCC1, the guanine nucleotide exchange factor (GEF) for Ran. We have used the Xenopus laevis egg extract system and in vitro assays of purified Proteins to examine how Ran or RCC1 could be involved in these numerous processes. In these studies, we employed mutant Ran Proteins to perturb nuclear assembly and function. The addition of a bacterially expressed mutant form of Ran (T24N-Ran), which was predicted to be primarily in the GDP-bound state, profoundly disrupted nuclear assembly and DNA replication in extracts. We further examined the molecular mechanism by which T24N-Ran disrupts normal nuclear activity and found that T24N-Ran binds tightly to the RCC1 Protein within the extract, resulting in its inactivation as a GEF. The capacity of T24N-Ran-blocked interphase extracts to assemble nuclei from de-membRanated sperm chromatin and to replicate their DNA could be restored by supplementing the extract with excess RCC1 and thereby providing excess GEF activity. Conversely, nuclear assembly and DNA replication were both rescued in extracts lacking RCC1 by the addition of high levels of wild-type GTP-bound Ran Protein, indicating that RCC1 does not have an essential function beyond its role as a GEF in interphase Xenopus extracts.
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A mutant form of the Ran/TC4 Protein disrupts nuclear function in Xenopus laevis egg extracts by inhibiting the RCC1 Protein, a regulator of chromosome condensation.
The EMBO Journal, 1994Co-Authors: Mary Dasso, T Ohba, T. Seki, Yoshiaki Azuma, T. NishimotoAbstract:Abstract The Ran Protein is a small GTPase that has been implicated in a large number of nuclear processes including tRansport. RNA processing and cell cycle checkpoint control. A similar spectrum of nuclear activities has been shown to require RCC1, the guanine nucleotide exchange factor (GEF) for Ran. We have used the Xenopus laevis egg extract system and in vitro assays of purified Proteins to examine how Ran or RCC1 could be involved in these numerous processes. In these studies, we employed mutant Ran Proteins to perturb nuclear assembly and function. The addition of a bacterially expressed mutant form of Ran (T24N-Ran), which was predicted to be primarily in the GDP-bound state, profoundly disrupted nuclear assembly and DNA replication in extracts. We further examined the molecular mechanism by which T24N-Ran disrupts normal nuclear activity and found that T24N-Ran binds tightly to the RCC1 Protein within the extract, resulting in its inactivation as a GEF. The capacity of T24N-Ran-blocked interphase extracts to assemble nuclei from de-membRanated sperm chromatin and to replicate their DNA could be restored by supplementing the extract with excess RCC1 and thereby providing excess GEF activity. Conversely, nuclear assembly and DNA replication were both rescued in extracts lacking RCC1 by the addition of high levels of wild-type GTP-bound Ran Protein, indicating that RCC1 does not have an essential function beyond its role as a GEF in interphase Xenopus extracts.
T. Seki - One of the best experts on this subject based on the ideXlab platform.
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a mutant form of the Ran tc4 Protein disrupts nuclear function in xenopus laevis egg extracts by inhibiting the rcc1 Protein a regulator of chromosome condensation
The EMBO Journal, 1994Co-Authors: Mary Dasso, T Ohba, T. Seki, Yoshiaki Azuma, T. NishimotoAbstract:Abstract The Ran Protein is a small GTPase that has been implicated in a large number of nuclear processes including tRansport. RNA processing and cell cycle checkpoint control. A similar spectrum of nuclear activities has been shown to require RCC1, the guanine nucleotide exchange factor (GEF) for Ran. We have used the Xenopus laevis egg extract system and in vitro assays of purified Proteins to examine how Ran or RCC1 could be involved in these numerous processes. In these studies, we employed mutant Ran Proteins to perturb nuclear assembly and function. The addition of a bacterially expressed mutant form of Ran (T24N-Ran), which was predicted to be primarily in the GDP-bound state, profoundly disrupted nuclear assembly and DNA replication in extracts. We further examined the molecular mechanism by which T24N-Ran disrupts normal nuclear activity and found that T24N-Ran binds tightly to the RCC1 Protein within the extract, resulting in its inactivation as a GEF. The capacity of T24N-Ran-blocked interphase extracts to assemble nuclei from de-membRanated sperm chromatin and to replicate their DNA could be restored by supplementing the extract with excess RCC1 and thereby providing excess GEF activity. Conversely, nuclear assembly and DNA replication were both rescued in extracts lacking RCC1 by the addition of high levels of wild-type GTP-bound Ran Protein, indicating that RCC1 does not have an essential function beyond its role as a GEF in interphase Xenopus extracts.
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A mutant form of the Ran/TC4 Protein disrupts nuclear function in Xenopus laevis egg extracts by inhibiting the RCC1 Protein, a regulator of chromosome condensation.
The EMBO Journal, 1994Co-Authors: Mary Dasso, T Ohba, T. Seki, Yoshiaki Azuma, T. NishimotoAbstract:Abstract The Ran Protein is a small GTPase that has been implicated in a large number of nuclear processes including tRansport. RNA processing and cell cycle checkpoint control. A similar spectrum of nuclear activities has been shown to require RCC1, the guanine nucleotide exchange factor (GEF) for Ran. We have used the Xenopus laevis egg extract system and in vitro assays of purified Proteins to examine how Ran or RCC1 could be involved in these numerous processes. In these studies, we employed mutant Ran Proteins to perturb nuclear assembly and function. The addition of a bacterially expressed mutant form of Ran (T24N-Ran), which was predicted to be primarily in the GDP-bound state, profoundly disrupted nuclear assembly and DNA replication in extracts. We further examined the molecular mechanism by which T24N-Ran disrupts normal nuclear activity and found that T24N-Ran binds tightly to the RCC1 Protein within the extract, resulting in its inactivation as a GEF. The capacity of T24N-Ran-blocked interphase extracts to assemble nuclei from de-membRanated sperm chromatin and to replicate their DNA could be restored by supplementing the extract with excess RCC1 and thereby providing excess GEF activity. Conversely, nuclear assembly and DNA replication were both rescued in extracts lacking RCC1 by the addition of high levels of wild-type GTP-bound Ran Protein, indicating that RCC1 does not have an essential function beyond its role as a GEF in interphase Xenopus extracts.
