Messenger RNA （mRNA） turnover in eukaryotic cells begins with shortening of the poly （A） tail at the 3＇ end, a process called deadenylation. In yeast, the deadenylation reaction is predominantly mediated by CCR4 ...Messenger RNA （mRNA） turnover in eukaryotic cells begins with shortening of the poly （A） tail at the 3＇ end, a process called deadenylation. In yeast, the deadenylation reaction is predominantly mediated by CCR4 and CCR4- associated factor 1 （CAF1）, two components of the well-characterised protein complex named CCR4-NOT. We report here that AtCAF1a and AtCAF1b, putative Arabidopsis homologs of the yeast CAF1 gene, partially complement the growth defect of the yeast call mutant in the presence of caffeine or at high temperatures. The expression of At-CAF1a and AtCAFlb is induced by multiple stress-related hormones and stimuli. Both AtCAF1a and AtCAFlb show deadenylation activity in vitro and point mutations in the predicted active sites disrupt this activity. T-DNA insertion mutants disrupting the expression of AtCAF1a and/or AtCAF1b are defective in deadenylation of stress-related mRNAs, indicating that the two AtCAF1 proteins are involved in regulated mRNA deadenylation in vivo. Interestingly, the single and double mutants of AtCAF1a and AtCAFlb show reduced expression of pathogenesis-related （PR） genes PR1 and PR2 and are more susceptible to Pseudomonas syringae pv tomato DC3000 （Pst DC3000） infection, whereas transgenic plants over-expressing AtCAFla show elevated expression of PR1 and PR2 and increased resis-tance to the same pathogen. Our results suggest roles of the AtCAF1 proteins in regulated mRNA deadenylation and defence responses to pathogen infections.展开更多
OBJECTIVE:To investigate the effects of icariin on apoptosis and the expression of Fas, Fas ligand(Fas L), B cell lymphoma(Bcl-2), and Bcl-2-associated X protein(Bax) in CD4+ T lymphocytes from patients with ankylosin...OBJECTIVE:To investigate the effects of icariin on apoptosis and the expression of Fas, Fas ligand(Fas L), B cell lymphoma(Bcl-2), and Bcl-2-associated X protein(Bax) in CD4+ T lymphocytes from patients with ankylosing spondylitis.METHODS:Primary cultures of peripheral blood CD4+ T lymphocytes were established and treated with icariin at high, medium, and low doses(0.5,0.25, and 0.125 mg/mL).Sulfasalazine treated and helthy cells were used as controls.Apoptosis of treated cells was determined by flow cytometry.Reverse transcription polymerase chain reaction and enzyme-linked immunosorbent assays were used to determine the effects of icariin on the expression of Fas, Fas L, Bcl-2, and Bax.The activity of caspase 8 and caspase 3 was determined by a colorimetric assay.RESULTS:The m RNA and protein expression of Fas,and activity of caspase 8 and caspase 3 in CD4+ T lymphocytes were increased by icariin(P < 0.05).Conversely, the m RNA and protein expression of Bcl-2 was decreased(P < 0.05).The expression of Fas L and Bax were not significantly different between groups.The proapoptotic effects of icariin were dose-dependent.CONCLUSION:Icariin induces the apoptosis of CD4 + T cells from patients with AS comparing to normal control.Therefore, the induction of apoptosis may be the likely mechanism of action of icariin's antirheumatics activities.展开更多
文摘Messenger RNA （mRNA） turnover in eukaryotic cells begins with shortening of the poly （A） tail at the 3＇ end, a process called deadenylation. In yeast, the deadenylation reaction is predominantly mediated by CCR4 and CCR4- associated factor 1 （CAF1）, two components of the well-characterised protein complex named CCR4-NOT. We report here that AtCAF1a and AtCAF1b, putative Arabidopsis homologs of the yeast CAF1 gene, partially complement the growth defect of the yeast call mutant in the presence of caffeine or at high temperatures. The expression of At-CAF1a and AtCAFlb is induced by multiple stress-related hormones and stimuli. Both AtCAF1a and AtCAFlb show deadenylation activity in vitro and point mutations in the predicted active sites disrupt this activity. T-DNA insertion mutants disrupting the expression of AtCAF1a and/or AtCAF1b are defective in deadenylation of stress-related mRNAs, indicating that the two AtCAF1 proteins are involved in regulated mRNA deadenylation in vivo. Interestingly, the single and double mutants of AtCAF1a and AtCAFlb show reduced expression of pathogenesis-related （PR） genes PR1 and PR2 and are more susceptible to Pseudomonas syringae pv tomato DC3000 （Pst DC3000） infection, whereas transgenic plants over-expressing AtCAFla show elevated expression of PR1 and PR2 and increased resis-tance to the same pathogen. Our results suggest roles of the AtCAF1 proteins in regulated mRNA deadenylation and defence responses to pathogen infections.
基金Supported by the Fundamental Research Funds for the Central Public Welfare Research Institutes:Pharmacogenomics of Tripterygium wilfordii Hook F response and liver toxic reaction in Rheumatoid Arthritis(No.ZZ0708079)the Fundamental Research Funds for the Central Public Welfare Research Institutes Pharmacogenomics of Tripterygium wilfordii Hook F response reaction in Rheumatoid Arthritis(No.31470962)
文摘OBJECTIVE:To investigate the effects of icariin on apoptosis and the expression of Fas, Fas ligand(Fas L), B cell lymphoma(Bcl-2), and Bcl-2-associated X protein(Bax) in CD4+ T lymphocytes from patients with ankylosing spondylitis.METHODS:Primary cultures of peripheral blood CD4+ T lymphocytes were established and treated with icariin at high, medium, and low doses(0.5,0.25, and 0.125 mg/mL).Sulfasalazine treated and helthy cells were used as controls.Apoptosis of treated cells was determined by flow cytometry.Reverse transcription polymerase chain reaction and enzyme-linked immunosorbent assays were used to determine the effects of icariin on the expression of Fas, Fas L, Bcl-2, and Bax.The activity of caspase 8 and caspase 3 was determined by a colorimetric assay.RESULTS:The m RNA and protein expression of Fas,and activity of caspase 8 and caspase 3 in CD4+ T lymphocytes were increased by icariin(P < 0.05).Conversely, the m RNA and protein expression of Bcl-2 was decreased(P < 0.05).The expression of Fas L and Bax were not significantly different between groups.The proapoptotic effects of icariin were dose-dependent.CONCLUSION:Icariin induces the apoptosis of CD4 + T cells from patients with AS comparing to normal control.Therefore, the induction of apoptosis may be the likely mechanism of action of icariin's antirheumatics activities.
