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Atsuhiko Shinmyo - One of the best experts on this subject based on the ideXlab platform.
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phosphorylation of retinoblastoma related protein by the cyclin d cyclin dependent Kinase Complex is activated at the g1 s phase transition in tobacco
The Plant Cell, 2002Co-Authors: Hirofumi Nakagami, Masami Sekine, Kazue Kawamura, Keiko Sugisaka, Atsuhiko ShinmyoAbstract:In mammals, D-type cyclin-associated Kinases mainly regulate the G1/S transition by phosphorylating the retinoblastoma (Rb) protein. We previously demonstrated that in tobacco, cyclin D (Nicta; CycD3;3) is Complexed with the PSTAIRE-containing Cyclin-Dependent Kinase (CDKA) from tobacco. Here, we show that Nicta; CycD3;3-associated Kinases phosphorylate both the tobacco Rb-related protein (NtRb1) and histone H1. Although NtRb1 Kinase activity was detected only during the middle G1- to early S-phase, histone H1 Kinase activity was observed as two peaks in G1- to S-phase and G2/M- to M-phase. Importantly, we show that the proportion of cells in the G1-phase was reduced in transgenic Bright Yellow-2 cells overexpressing Nicta; CycD3;3-GFP. Mutational analyses revealed that phosphorylation of Thr-191 in Nicta; CycD3;3 possibly is required for both full Kinase activity and localization predominantly to the nucleus. These data suggest that Nicta; CycD3;3 acts as a rate-limiting regulator in the G1/S transition by forming active Complexes with CDKA or its related Kinases to phosphorylate Rb-related protein and potentially plays a novel role during G2/M and mitosis.
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Phosphorylation of Retinoblastoma-Related Protein by the Cyclin D/Cyclin-Dependent Kinase Complex Is Activated at the G1/S-Phase Transition in Tobacco
The Plant cell, 2002Co-Authors: Hirofumi Nakagami, Masami Sekine, Kazue Kawamura, Keiko Sugisaka, Atsuhiko ShinmyoAbstract:In mammals, D-type cyclin-associated Kinases mainly regulate the G1/S transition by phosphorylating the retinoblastoma (Rb) protein. We previously demonstrated that in tobacco, cyclin D (Nicta; CycD3;3) is Complexed with the PSTAIRE-containing Cyclin-Dependent Kinase (CDKA) from tobacco. Here, we show that Nicta; CycD3;3-associated Kinases phosphorylate both the tobacco Rb-related protein (NtRb1) and histone H1. Although NtRb1 Kinase activity was detected only during the middle G1- to early S-phase, histone H1 Kinase activity was observed as two peaks in G1- to S-phase and G2/M- to M-phase. Importantly, we show that the proportion of cells in the G1-phase was reduced in transgenic Bright Yellow-2 cells overexpressing Nicta; CycD3;3-GFP. Mutational analyses revealed that phosphorylation of Thr-191 in Nicta; CycD3;3 possibly is required for both full Kinase activity and localization predominantly to the nucleus. These data suggest that Nicta; CycD3;3 acts as a rate-limiting regulator in the G1/S transition by forming active Complexes with CDKA or its related Kinases to phosphorylate Rb-related protein and potentially plays a novel role during G2/M and mitosis.
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tobacco retinoblastoma related protein phosphorylated by a distinct cyclin dependent Kinase Complex with cdc2 cyclin d in vitro
Plant Journal, 1999Co-Authors: Hirofumi Nakagami, Masami Sekine, Hiroko Murakami, Atsuhiko ShinmyoAbstract:Summary The retinoblastoma (Rb) protein was originally identified as a product of a tumour suppressor gene that plays a pivotal role in regulating both the cell cycle and differentiation in mammals. The growth-suppressive activity of Rb is regulated by phosphorylation with Cyclin-Dependent Kinase (CDK), and inactivation of the Rb function is one of the critical steps for transition from the G1 to the S phase. We report here the cloning of a cDNA (NtRb1) from Nicotiana tabacum which encodes a Rb-related protein, and show that this gene is expressed in all the organs examined at the mRNA level. We have demonstrated that NtRb1 interacts with tobacco cyclin D by using yeast two-hybrid and in vitro binding assays. In mammals, cyclin D can assemble with CDK4 and CDK6, but not with Cdc2, to form active Complexes. Surprisingly, tobacco cyclin D and Cdc2 proteins can form a Complex in insect cells, which is able to phosphorylate tobacco Rb-related protein in vitro. Using immunoprecipitation with the anti-cyclin D antibody, cyclin D can be found in a Complex with Cdc2 in suspension-cultured tobacco BY-2 cells. These results suggest that the cdc2 gene modulates the cell cycle through the phosphorylation of Rb-related protein by forming an active Complex with cyclin D in plants.
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Tobacco retinoblastoma-related protein phosphorylated by a distinct Cyclin-Dependent Kinase Complex with Cdc2/cyclin D in vitro.
The Plant Journal, 1999Co-Authors: Hirofumi Nakagami, Masami Sekine, Hiroko Murakami, Atsuhiko ShinmyoAbstract:Summary The retinoblastoma (Rb) protein was originally identified as a product of a tumour suppressor gene that plays a pivotal role in regulating both the cell cycle and differentiation in mammals. The growth-suppressive activity of Rb is regulated by phosphorylation with Cyclin-Dependent Kinase (CDK), and inactivation of the Rb function is one of the critical steps for transition from the G1 to the S phase. We report here the cloning of a cDNA (NtRb1) from Nicotiana tabacum which encodes a Rb-related protein, and show that this gene is expressed in all the organs examined at the mRNA level. We have demonstrated that NtRb1 interacts with tobacco cyclin D by using yeast two-hybrid and in vitro binding assays. In mammals, cyclin D can assemble with CDK4 and CDK6, but not with Cdc2, to form active Complexes. Surprisingly, tobacco cyclin D and Cdc2 proteins can form a Complex in insect cells, which is able to phosphorylate tobacco Rb-related protein in vitro. Using immunoprecipitation with the anti-cyclin D antibody, cyclin D can be found in a Complex with Cdc2 in suspension-cultured tobacco BY-2 cells. These results suggest that the cdc2 gene modulates the cell cycle through the phosphorylation of Rb-related protein by forming an active Complex with cyclin D in plants.
Hiroyuki Kuramoto - One of the best experts on this subject based on the ideXlab platform.
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paradoxical expression of cell cycle inhibitor p27 in endometrioid adenocarcinoma of the uterine corpus correlation with proliferation and clinicopathological parameters
British Journal of Cancer, 2002Co-Authors: Jun Watanabe, H Sato, Tadayuki Kanai, Y. Kamata, Toshiko Jobo, T. Fujisawa, Eiji Ohno, Toru Kameya, H Hata, Hiroyuki KuramotoAbstract:p27 is regarded as a Cyclin-Dependent Kinase inhibitor of the G1-to-S cell cycle progression by suppressing the Kinase activity of cyclin/Cyclin-Dependent Kinase Complex. This study aimed to investigate p27 expression in the normal endometrium and endometrioid adenocarcinoma of the uterine corpus and the correlation of its expression with cell proliferation and clinicopathological parameters. Tissue samples of 127 endometrioid adenocarcinomas and 15 normal endometria were used in the study. Immunohistochemical staining for detecting p27 and Ki-67 was performed by the labelled streptavidin-biotin method on formalin-fixed and paraffin-embedded tissue samples. The expression was given as the labelling index, which indicates the percentage of positive nuclei. p27 staining was observed in the nuclei of the glandular cells in the functional layer of the secretory phase endometrium, whereas it was negative in those of the proliferative phase. In endometrioid adenocarcinomas, the labelling index of p27 expression paradoxically increased more significantly in the higher histological grades and was correlated with that of Ki-67. The high level of p27 expression was associated with clinicopathological parameters such as FIGO stage, lymph node metastasis, lymphovascular space involvement and myometrial invasion. High p27 expression was linked to higher grades of endometrioid adenocarcinoma, cell proliferation and some clinical prognostic factors. These results indicate that p27 might be an indicator of poor prognosis. British Journal of Cancer (2002) 87, 81–85. doi:10.1038/sj.bjc.6600434 www.bjcancer.com © 2002 Cancer Research UK
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Paradoxical expression of cell cycle inhibitor p27 in endometrioid adenocarcinoma of the uterine corpus - correlation with proliferation and clinicopathological parameters.
British journal of cancer, 2002Co-Authors: Jun Watanabe, H Sato, Tadayuki Kanai, Y. Kamata, Toshiko Jobo, Hata H, T. Fujisawa, Eiji Ohno, Toru Kameya, Hiroyuki KuramotoAbstract:p27 is regarded as a Cyclin-Dependent Kinase inhibitor of the G1-to-S cell cycle progression by suppressing the Kinase activity of cyclin/Cyclin-Dependent Kinase Complex. This study aimed to investigate p27 expression in the normal endometrium and endometrioid adenocarcinoma of the uterine corpus and the correlation of its expression with cell proliferation and clinicopathological parameters. Tissue samples of 127 endometrioid adenocarcinomas and 15 normal endometria were used in the study. Immunohistochemical staining for detecting p27 and Ki-67 was performed by the labelled streptavidin-biotin method on formalin-fixed and paraffin-embedded tissue samples. The expression was given as the labelling index, which indicates the percentage of positive nuclei. p27 staining was observed in the nuclei of the glandular cells in the functional layer of the secretory phase endometrium, whereas it was negative in those of the proliferative phase. In endometrioid adenocarcinomas, the labelling index of p27 expression paradoxically increased more significantly in the higher histological grades and was correlated with that of Ki-67. The high level of p27 expression was associated with clinicopathological parameters such as FIGO stage, lymph node metastasis, lymphovascular space involvement and myometrial invasion. High p27 expression was linked to higher grades of endometrioid adenocarcinoma, cell proliferation and some clinical prognostic factors. These results indicate that p27 might be an indicator of poor prognosis.
Hirofumi Nakagami - One of the best experts on this subject based on the ideXlab platform.
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phosphorylation of retinoblastoma related protein by the cyclin d cyclin dependent Kinase Complex is activated at the g1 s phase transition in tobacco
The Plant Cell, 2002Co-Authors: Hirofumi Nakagami, Masami Sekine, Kazue Kawamura, Keiko Sugisaka, Atsuhiko ShinmyoAbstract:In mammals, D-type cyclin-associated Kinases mainly regulate the G1/S transition by phosphorylating the retinoblastoma (Rb) protein. We previously demonstrated that in tobacco, cyclin D (Nicta; CycD3;3) is Complexed with the PSTAIRE-containing Cyclin-Dependent Kinase (CDKA) from tobacco. Here, we show that Nicta; CycD3;3-associated Kinases phosphorylate both the tobacco Rb-related protein (NtRb1) and histone H1. Although NtRb1 Kinase activity was detected only during the middle G1- to early S-phase, histone H1 Kinase activity was observed as two peaks in G1- to S-phase and G2/M- to M-phase. Importantly, we show that the proportion of cells in the G1-phase was reduced in transgenic Bright Yellow-2 cells overexpressing Nicta; CycD3;3-GFP. Mutational analyses revealed that phosphorylation of Thr-191 in Nicta; CycD3;3 possibly is required for both full Kinase activity and localization predominantly to the nucleus. These data suggest that Nicta; CycD3;3 acts as a rate-limiting regulator in the G1/S transition by forming active Complexes with CDKA or its related Kinases to phosphorylate Rb-related protein and potentially plays a novel role during G2/M and mitosis.
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Phosphorylation of Retinoblastoma-Related Protein by the Cyclin D/Cyclin-Dependent Kinase Complex Is Activated at the G1/S-Phase Transition in Tobacco
The Plant cell, 2002Co-Authors: Hirofumi Nakagami, Masami Sekine, Kazue Kawamura, Keiko Sugisaka, Atsuhiko ShinmyoAbstract:In mammals, D-type cyclin-associated Kinases mainly regulate the G1/S transition by phosphorylating the retinoblastoma (Rb) protein. We previously demonstrated that in tobacco, cyclin D (Nicta; CycD3;3) is Complexed with the PSTAIRE-containing Cyclin-Dependent Kinase (CDKA) from tobacco. Here, we show that Nicta; CycD3;3-associated Kinases phosphorylate both the tobacco Rb-related protein (NtRb1) and histone H1. Although NtRb1 Kinase activity was detected only during the middle G1- to early S-phase, histone H1 Kinase activity was observed as two peaks in G1- to S-phase and G2/M- to M-phase. Importantly, we show that the proportion of cells in the G1-phase was reduced in transgenic Bright Yellow-2 cells overexpressing Nicta; CycD3;3-GFP. Mutational analyses revealed that phosphorylation of Thr-191 in Nicta; CycD3;3 possibly is required for both full Kinase activity and localization predominantly to the nucleus. These data suggest that Nicta; CycD3;3 acts as a rate-limiting regulator in the G1/S transition by forming active Complexes with CDKA or its related Kinases to phosphorylate Rb-related protein and potentially plays a novel role during G2/M and mitosis.
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tobacco retinoblastoma related protein phosphorylated by a distinct cyclin dependent Kinase Complex with cdc2 cyclin d in vitro
Plant Journal, 1999Co-Authors: Hirofumi Nakagami, Masami Sekine, Hiroko Murakami, Atsuhiko ShinmyoAbstract:Summary The retinoblastoma (Rb) protein was originally identified as a product of a tumour suppressor gene that plays a pivotal role in regulating both the cell cycle and differentiation in mammals. The growth-suppressive activity of Rb is regulated by phosphorylation with Cyclin-Dependent Kinase (CDK), and inactivation of the Rb function is one of the critical steps for transition from the G1 to the S phase. We report here the cloning of a cDNA (NtRb1) from Nicotiana tabacum which encodes a Rb-related protein, and show that this gene is expressed in all the organs examined at the mRNA level. We have demonstrated that NtRb1 interacts with tobacco cyclin D by using yeast two-hybrid and in vitro binding assays. In mammals, cyclin D can assemble with CDK4 and CDK6, but not with Cdc2, to form active Complexes. Surprisingly, tobacco cyclin D and Cdc2 proteins can form a Complex in insect cells, which is able to phosphorylate tobacco Rb-related protein in vitro. Using immunoprecipitation with the anti-cyclin D antibody, cyclin D can be found in a Complex with Cdc2 in suspension-cultured tobacco BY-2 cells. These results suggest that the cdc2 gene modulates the cell cycle through the phosphorylation of Rb-related protein by forming an active Complex with cyclin D in plants.
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Tobacco retinoblastoma-related protein phosphorylated by a distinct Cyclin-Dependent Kinase Complex with Cdc2/cyclin D in vitro.
The Plant Journal, 1999Co-Authors: Hirofumi Nakagami, Masami Sekine, Hiroko Murakami, Atsuhiko ShinmyoAbstract:Summary The retinoblastoma (Rb) protein was originally identified as a product of a tumour suppressor gene that plays a pivotal role in regulating both the cell cycle and differentiation in mammals. The growth-suppressive activity of Rb is regulated by phosphorylation with Cyclin-Dependent Kinase (CDK), and inactivation of the Rb function is one of the critical steps for transition from the G1 to the S phase. We report here the cloning of a cDNA (NtRb1) from Nicotiana tabacum which encodes a Rb-related protein, and show that this gene is expressed in all the organs examined at the mRNA level. We have demonstrated that NtRb1 interacts with tobacco cyclin D by using yeast two-hybrid and in vitro binding assays. In mammals, cyclin D can assemble with CDK4 and CDK6, but not with Cdc2, to form active Complexes. Surprisingly, tobacco cyclin D and Cdc2 proteins can form a Complex in insect cells, which is able to phosphorylate tobacco Rb-related protein in vitro. Using immunoprecipitation with the anti-cyclin D antibody, cyclin D can be found in a Complex with Cdc2 in suspension-cultured tobacco BY-2 cells. These results suggest that the cdc2 gene modulates the cell cycle through the phosphorylation of Rb-related protein by forming an active Complex with cyclin D in plants.
Jun Watanabe - One of the best experts on this subject based on the ideXlab platform.
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paradoxical expression of cell cycle inhibitor p27 in endometrioid adenocarcinoma of the uterine corpus correlation with proliferation and clinicopathological parameters
British Journal of Cancer, 2002Co-Authors: Jun Watanabe, H Sato, Tadayuki Kanai, Y. Kamata, Toshiko Jobo, T. Fujisawa, Eiji Ohno, Toru Kameya, H Hata, Hiroyuki KuramotoAbstract:p27 is regarded as a Cyclin-Dependent Kinase inhibitor of the G1-to-S cell cycle progression by suppressing the Kinase activity of cyclin/Cyclin-Dependent Kinase Complex. This study aimed to investigate p27 expression in the normal endometrium and endometrioid adenocarcinoma of the uterine corpus and the correlation of its expression with cell proliferation and clinicopathological parameters. Tissue samples of 127 endometrioid adenocarcinomas and 15 normal endometria were used in the study. Immunohistochemical staining for detecting p27 and Ki-67 was performed by the labelled streptavidin-biotin method on formalin-fixed and paraffin-embedded tissue samples. The expression was given as the labelling index, which indicates the percentage of positive nuclei. p27 staining was observed in the nuclei of the glandular cells in the functional layer of the secretory phase endometrium, whereas it was negative in those of the proliferative phase. In endometrioid adenocarcinomas, the labelling index of p27 expression paradoxically increased more significantly in the higher histological grades and was correlated with that of Ki-67. The high level of p27 expression was associated with clinicopathological parameters such as FIGO stage, lymph node metastasis, lymphovascular space involvement and myometrial invasion. High p27 expression was linked to higher grades of endometrioid adenocarcinoma, cell proliferation and some clinical prognostic factors. These results indicate that p27 might be an indicator of poor prognosis. British Journal of Cancer (2002) 87, 81–85. doi:10.1038/sj.bjc.6600434 www.bjcancer.com © 2002 Cancer Research UK
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Paradoxical expression of cell cycle inhibitor p27 in endometrioid adenocarcinoma of the uterine corpus - correlation with proliferation and clinicopathological parameters.
British journal of cancer, 2002Co-Authors: Jun Watanabe, H Sato, Tadayuki Kanai, Y. Kamata, Toshiko Jobo, Hata H, T. Fujisawa, Eiji Ohno, Toru Kameya, Hiroyuki KuramotoAbstract:p27 is regarded as a Cyclin-Dependent Kinase inhibitor of the G1-to-S cell cycle progression by suppressing the Kinase activity of cyclin/Cyclin-Dependent Kinase Complex. This study aimed to investigate p27 expression in the normal endometrium and endometrioid adenocarcinoma of the uterine corpus and the correlation of its expression with cell proliferation and clinicopathological parameters. Tissue samples of 127 endometrioid adenocarcinomas and 15 normal endometria were used in the study. Immunohistochemical staining for detecting p27 and Ki-67 was performed by the labelled streptavidin-biotin method on formalin-fixed and paraffin-embedded tissue samples. The expression was given as the labelling index, which indicates the percentage of positive nuclei. p27 staining was observed in the nuclei of the glandular cells in the functional layer of the secretory phase endometrium, whereas it was negative in those of the proliferative phase. In endometrioid adenocarcinomas, the labelling index of p27 expression paradoxically increased more significantly in the higher histological grades and was correlated with that of Ki-67. The high level of p27 expression was associated with clinicopathological parameters such as FIGO stage, lymph node metastasis, lymphovascular space involvement and myometrial invasion. High p27 expression was linked to higher grades of endometrioid adenocarcinoma, cell proliferation and some clinical prognostic factors. These results indicate that p27 might be an indicator of poor prognosis.
Jeremy C. Mottram - One of the best experts on this subject based on the ideXlab platform.
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Isolation of Trypanosoma brucei CYC2 and CYC3 cyclin genes by rescue of a yeast G(1) cyclin mutant. Functional characterization of CYC2.
The Journal of biological chemistry, 2000Co-Authors: Jaap J. Van Hellemond, Philippe Neuville, Ralph T. Schwarz, Keith R. Matthews, Jeremy C. MottramAbstract:Two Trypanosoma brucei cyclin genes, CYC2 and CYC3, have been isolated by rescue of the Saccharomyces cerevisiae mutant DL1, which is deficient in CLN G(1) cyclin function. CYC2 encodes a 24-kDa protein that has sequence identity to the Neurospora crassa PREG1 and the S. cerevisiae PHO80 cyclin. CYC3 has the most sequence identity to mitotic B-type cyclins from a variety of organisms. Both CYC2 and CYC3 are single-copy genes and expressed in all life cycle stages of the parasite. To determine if CYC2 is found in a Complex with previously identified trypanosome cdc2-related Kinases (CRKs), the CYC2 gene was fused to the TY epitope tag, integrated into the trypanosome genome, and expressed under inducible control. CYC2ty was found to associate with an active trypanosome CRK Complex since CYC2ty bound to leishmanial p12(cks1), and histone H1 Kinase activity was detected in CYC2ty immune-precipitated fractions. Gene knockout experiments provide evidence that CYC2 is an essential gene, and co-immune precipitations together with a two-hybrid interaction assay demonstrated that CYC2 interacts with CRK3. The CRK3 x CYC2ty Complex, the first Cyclin-Dependent Kinase Complex identified in trypanosomes, was localized by immune fluorescence to the cytoplasm throughout the cell cycle.
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Isolation of Trypanosoma brucei CYC2 and CYC3 Cyclin Genes by Rescue of a Yeast G 1 Cyclin Mutant
2000Co-Authors: Jaap J. Van Hellemond, Philippe Neuville, Ralph T. Schwarz, Keith R. Matthewsi, Jeremy C. MottramAbstract:Two Trypanosoma brucei cyclin genes, CYC2 and CYC3, have been isolated by rescue of the Saccharomyces cerevisiae mutant DL1, which is deficient in CLN G1 cyclin function. CYC2 encodes a 24-kDa protein that has sequence identity to the Neurospora crassa PREG1 and the S. cerevisiae PHO80 cyclin. CYC3 has the most sequence identity to mitotic B-type cyclins from a variety of organisms. Both CYC2 and CYC3 are single-copy genes and expressed in all life cycle stages of the parasite. To determine if CYC2 is found in a Complex with previously identified trypanosome cdc2-related Kinases (CRKs), the CYC2 gene was fused to the TY epitope tag, integrated into the trypanosome genome, and expressed under inducible control. CYC2ty was found to associate with an active trypanosome CRK Complex since CYC2ty bound to leishmanial p12 cks1 , and histone H1 Kinase activity was detected in CYC2ty immune-precipitated fractions. Gene knockout experiments provide evidence that CYC2 is an essential gene, and co-immune precipitations together with a two-hybrid interaction assay demonstrated that CYC2 interacts with CRK3. The CRK3zCYC2ty Complex, the first Cyclin-Dependent Kinase Complex identified in trypanosomes, was localized by immune fluorescence to the cytoplasm throughout the cell cycle.
