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Gabriel Guarneros - One of the best experts on this subject based on the ideXlab platform.
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Excess of charged tRNALys maintains low levels of peptidyl-tRNA hydrolase in pth(Ts) mutants at a non-Permissive Temperature
Nucleic Acids Research, 2006Co-Authors: Serafín Vivanco-domínguez, L. Rogelio Cruz-vera, Gabriel GuarnerosAbstract:Cellular changes have been monitored during the suppression, mediated by the overproduction of tRNA Lys , of thermosensitivity in Escherichia coli strain AA7852 carrying a mutation in peptidyl-tRNA hydrolase (Pth) encoded by the pth(Ts) gene. The presence in AA7852 cells of a plasmid bearing lysV gene helped to maintain low levels of the unstable Pth(Ts) protein and to preserve the viability of the mutant line at 41 � C whereas plasmids bearing other tRNA genes were ineffective. At 32 � C the excess of tRNA Lys did not alter the percentages of the free-, charged- or peptidyl-tRNA Lys species compared with those found in strains that did not overproduce tRNA Lys .A t 41 � C, however, despite increases in the level of peptidyl-tRNA Lys , the excess tRNA Lys helped to maintain the concentration of charged-tRNA Lys at a level comparable with that found in non-overproducer cells grown at a Permissive Temperature. In addition, the excess tRNA Lys at 41 � C provoked a reduction in the concentrations of various peptidyl-tRNAs, which normally accumulate in pth(Ts) cells, and a proportional increase in the concentrations of the corresponding aminoacyl-tRNAs. The possible mechanism of rescue due to the overexpression of tRNA Lys and the causes of tRNA Lys starvation in
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Excess of charged tRNALys maintains low levels of peptidyl-tRNA hydrolase in pth(Ts) mutants at a non-Permissive Temperature
Nucleic acids research, 2006Co-Authors: Serafín Vivanco-domínguez, L. Rogelio Cruz-vera, Gabriel GuarnerosAbstract:Cellular changes have been monitored during the suppression, mediated by the overproduction of tRNA(Lys), of thermosensitivity in Escherichia coli strain AA7852 carrying a mutation in peptidyl-tRNA hydrolase (Pth) encoded by the pth(Ts) gene. The presence in AA7852 cells of a plasmid bearing lysV gene helped to maintain low levels of the unstable Pth(Ts) protein and to preserve the viability of the mutant line at 41 degrees C whereas plasmids bearing other tRNA genes were ineffective. At 32 degrees C the excess of tRNA(Lys) did not alter the percentages of the free-, charged- or peptidyl-tRNA(Lys) species compared with those found in strains that did not overproduce tRNA(Lys). At 41 degrees C, however, despite increases in the level of peptidyl-tRNA(Lys), the excess tRNA(Lys) helped to maintain the concentration of charged-tRNA(Lys) at a level comparable with that found in non-overproducer cells grown at a Permissive Temperature. In addition, the excess tRNA(Lys) at 41 degrees C provoked a reduction in the concentrations of various peptidyl-tRNAs, which normally accumulate in pth(Ts) cells, and a proportional increase in the concentrations of the corresponding aminoacyl-tRNAs. The possible mechanism of rescue due to the overexpression of tRNA(Lys) and the causes of tRNA(Lys) starvation in pth(Ts) strains grown at non-Permissive Temperatures are considered.
Serafín Vivanco-domínguez - One of the best experts on this subject based on the ideXlab platform.
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Excess of charged tRNALys maintains low levels of peptidyl-tRNA hydrolase in pth(Ts) mutants at a non-Permissive Temperature
Nucleic Acids Research, 2006Co-Authors: Serafín Vivanco-domínguez, L. Rogelio Cruz-vera, Gabriel GuarnerosAbstract:Cellular changes have been monitored during the suppression, mediated by the overproduction of tRNA Lys , of thermosensitivity in Escherichia coli strain AA7852 carrying a mutation in peptidyl-tRNA hydrolase (Pth) encoded by the pth(Ts) gene. The presence in AA7852 cells of a plasmid bearing lysV gene helped to maintain low levels of the unstable Pth(Ts) protein and to preserve the viability of the mutant line at 41 � C whereas plasmids bearing other tRNA genes were ineffective. At 32 � C the excess of tRNA Lys did not alter the percentages of the free-, charged- or peptidyl-tRNA Lys species compared with those found in strains that did not overproduce tRNA Lys .A t 41 � C, however, despite increases in the level of peptidyl-tRNA Lys , the excess tRNA Lys helped to maintain the concentration of charged-tRNA Lys at a level comparable with that found in non-overproducer cells grown at a Permissive Temperature. In addition, the excess tRNA Lys at 41 � C provoked a reduction in the concentrations of various peptidyl-tRNAs, which normally accumulate in pth(Ts) cells, and a proportional increase in the concentrations of the corresponding aminoacyl-tRNAs. The possible mechanism of rescue due to the overexpression of tRNA Lys and the causes of tRNA Lys starvation in
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Excess of charged tRNALys maintains low levels of peptidyl-tRNA hydrolase in pth(Ts) mutants at a non-Permissive Temperature
Nucleic acids research, 2006Co-Authors: Serafín Vivanco-domínguez, L. Rogelio Cruz-vera, Gabriel GuarnerosAbstract:Cellular changes have been monitored during the suppression, mediated by the overproduction of tRNA(Lys), of thermosensitivity in Escherichia coli strain AA7852 carrying a mutation in peptidyl-tRNA hydrolase (Pth) encoded by the pth(Ts) gene. The presence in AA7852 cells of a plasmid bearing lysV gene helped to maintain low levels of the unstable Pth(Ts) protein and to preserve the viability of the mutant line at 41 degrees C whereas plasmids bearing other tRNA genes were ineffective. At 32 degrees C the excess of tRNA(Lys) did not alter the percentages of the free-, charged- or peptidyl-tRNA(Lys) species compared with those found in strains that did not overproduce tRNA(Lys). At 41 degrees C, however, despite increases in the level of peptidyl-tRNA(Lys), the excess tRNA(Lys) helped to maintain the concentration of charged-tRNA(Lys) at a level comparable with that found in non-overproducer cells grown at a Permissive Temperature. In addition, the excess tRNA(Lys) at 41 degrees C provoked a reduction in the concentrations of various peptidyl-tRNAs, which normally accumulate in pth(Ts) cells, and a proportional increase in the concentrations of the corresponding aminoacyl-tRNAs. The possible mechanism of rescue due to the overexpression of tRNA(Lys) and the causes of tRNA(Lys) starvation in pth(Ts) strains grown at non-Permissive Temperatures are considered.
L. Rogelio Cruz-vera - One of the best experts on this subject based on the ideXlab platform.
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Excess of charged tRNALys maintains low levels of peptidyl-tRNA hydrolase in pth(Ts) mutants at a non-Permissive Temperature
Nucleic Acids Research, 2006Co-Authors: Serafín Vivanco-domínguez, L. Rogelio Cruz-vera, Gabriel GuarnerosAbstract:Cellular changes have been monitored during the suppression, mediated by the overproduction of tRNA Lys , of thermosensitivity in Escherichia coli strain AA7852 carrying a mutation in peptidyl-tRNA hydrolase (Pth) encoded by the pth(Ts) gene. The presence in AA7852 cells of a plasmid bearing lysV gene helped to maintain low levels of the unstable Pth(Ts) protein and to preserve the viability of the mutant line at 41 � C whereas plasmids bearing other tRNA genes were ineffective. At 32 � C the excess of tRNA Lys did not alter the percentages of the free-, charged- or peptidyl-tRNA Lys species compared with those found in strains that did not overproduce tRNA Lys .A t 41 � C, however, despite increases in the level of peptidyl-tRNA Lys , the excess tRNA Lys helped to maintain the concentration of charged-tRNA Lys at a level comparable with that found in non-overproducer cells grown at a Permissive Temperature. In addition, the excess tRNA Lys at 41 � C provoked a reduction in the concentrations of various peptidyl-tRNAs, which normally accumulate in pth(Ts) cells, and a proportional increase in the concentrations of the corresponding aminoacyl-tRNAs. The possible mechanism of rescue due to the overexpression of tRNA Lys and the causes of tRNA Lys starvation in
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Excess of charged tRNALys maintains low levels of peptidyl-tRNA hydrolase in pth(Ts) mutants at a non-Permissive Temperature
Nucleic acids research, 2006Co-Authors: Serafín Vivanco-domínguez, L. Rogelio Cruz-vera, Gabriel GuarnerosAbstract:Cellular changes have been monitored during the suppression, mediated by the overproduction of tRNA(Lys), of thermosensitivity in Escherichia coli strain AA7852 carrying a mutation in peptidyl-tRNA hydrolase (Pth) encoded by the pth(Ts) gene. The presence in AA7852 cells of a plasmid bearing lysV gene helped to maintain low levels of the unstable Pth(Ts) protein and to preserve the viability of the mutant line at 41 degrees C whereas plasmids bearing other tRNA genes were ineffective. At 32 degrees C the excess of tRNA(Lys) did not alter the percentages of the free-, charged- or peptidyl-tRNA(Lys) species compared with those found in strains that did not overproduce tRNA(Lys). At 41 degrees C, however, despite increases in the level of peptidyl-tRNA(Lys), the excess tRNA(Lys) helped to maintain the concentration of charged-tRNA(Lys) at a level comparable with that found in non-overproducer cells grown at a Permissive Temperature. In addition, the excess tRNA(Lys) at 41 degrees C provoked a reduction in the concentrations of various peptidyl-tRNAs, which normally accumulate in pth(Ts) cells, and a proportional increase in the concentrations of the corresponding aminoacyl-tRNAs. The possible mechanism of rescue due to the overexpression of tRNA(Lys) and the causes of tRNA(Lys) starvation in pth(Ts) strains grown at non-Permissive Temperatures are considered.
Tetsuro Sumi - One of the best experts on this subject based on the ideXlab platform.
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Suppression of tumorigenicity in Temperature-sensitive mutants of embryonal carcinoma cells by induction of cell differentiation at non-Permissive Temperature.
International journal of cancer, 1993Co-Authors: Tetsuro Sumi, Masayoshi Sakuda, Yukio Nishina, Mitsuko Kosaka, Yoshitakc NishimuneAbstract:The Temperature-sensitive (ts) mutants of cell differentiation derived from the mouse teratocarcinoma cell line F9, when exposed to non-Permissive Temperature, undergo stem-cell differentiation concomitant with a transient retardation of cell-cycle progression. By incubating these mutant strains at non-Permissive Temperature, we were able to study the relationship between cell differentiation and tumorigenicity. Upon exposure to non-Permissive Temperature, the mutant cells undergo extensive differentiation and lose their ability to initiate tumors in vivo, but retain their in vitro proliferative potential. Our data suggest that the loss of tumorigenicity is not caused by altered proliferative potential, but rather by cell differentiation. We therefore suggest that the loss of proliferative potential and the onset of cell differentiation in teratocarcinoma F9 cells are 2 independent events which can be genetically dissected, and that there is (a) crucial step(s) in the differentiation pathway at which these ts mutant cells lose their tumorigenicity.
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c-myc and p53 gene expression in the differentiation of Temperature-sensitive mutants of teratocarcinoma F9 cells.
Oncogene, 1992Co-Authors: Mitsuko Kosaka, Tetsuro Sumi, Yukio Nishina, S. Iwai, Yoshitake NishimuneAbstract:We have previously reported the isolation of several Temperature-sensitive (ts) mutants of F9 cells. Further investigations showed that some mutants were induced to differentiate at non-Permissive Temperature of cell growth, accompanied by changes in the expression of various genes, whereas others were not. During the differentiation induced by shifting up to the non-Permissive Temperature, a rapid and transient decrease in both c-myc and p53 mRNA levels and rapid induction of c-jun mRNA were observed. These changes were specific in differentiation-inducible mutants and were not observed in a non-inducible mutant. In both types of mutants, the level of c-myc mRNA decreased in association with growth retardation at the non-Permissive Temperature. The p53 mRNA, however, showed specific increase in the differentiation-inducible ts mutants. These observations suggest distinct roles for p53 and c-myc from proliferation to differentiation in teratocarcinoma stem cells.
Mitsuko Kosaka - One of the best experts on this subject based on the ideXlab platform.
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Suppression of tumorigenicity in Temperature-sensitive mutants of embryonal carcinoma cells by induction of cell differentiation at non-Permissive Temperature.
International journal of cancer, 1993Co-Authors: Tetsuro Sumi, Masayoshi Sakuda, Yukio Nishina, Mitsuko Kosaka, Yoshitakc NishimuneAbstract:The Temperature-sensitive (ts) mutants of cell differentiation derived from the mouse teratocarcinoma cell line F9, when exposed to non-Permissive Temperature, undergo stem-cell differentiation concomitant with a transient retardation of cell-cycle progression. By incubating these mutant strains at non-Permissive Temperature, we were able to study the relationship between cell differentiation and tumorigenicity. Upon exposure to non-Permissive Temperature, the mutant cells undergo extensive differentiation and lose their ability to initiate tumors in vivo, but retain their in vitro proliferative potential. Our data suggest that the loss of tumorigenicity is not caused by altered proliferative potential, but rather by cell differentiation. We therefore suggest that the loss of proliferative potential and the onset of cell differentiation in teratocarcinoma F9 cells are 2 independent events which can be genetically dissected, and that there is (a) crucial step(s) in the differentiation pathway at which these ts mutant cells lose their tumorigenicity.
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c-myc and p53 gene expression in the differentiation of Temperature-sensitive mutants of teratocarcinoma F9 cells.
Oncogene, 1992Co-Authors: Mitsuko Kosaka, Tetsuro Sumi, Yukio Nishina, S. Iwai, Yoshitake NishimuneAbstract:We have previously reported the isolation of several Temperature-sensitive (ts) mutants of F9 cells. Further investigations showed that some mutants were induced to differentiate at non-Permissive Temperature of cell growth, accompanied by changes in the expression of various genes, whereas others were not. During the differentiation induced by shifting up to the non-Permissive Temperature, a rapid and transient decrease in both c-myc and p53 mRNA levels and rapid induction of c-jun mRNA were observed. These changes were specific in differentiation-inducible mutants and were not observed in a non-inducible mutant. In both types of mutants, the level of c-myc mRNA decreased in association with growth retardation at the non-Permissive Temperature. The p53 mRNA, however, showed specific increase in the differentiation-inducible ts mutants. These observations suggest distinct roles for p53 and c-myc from proliferation to differentiation in teratocarcinoma stem cells.