Termination of translation in eukaryotes requires two polypeptide chain-release factors, eRF1 and eRF3. eRF1 recognizes stop signals, whereas eRF3 is a ribosome-dependent and eRFl-dependent GTPase. Polypeptide release...Termination of translation in eukaryotes requires two polypeptide chain-release factors, eRF1 and eRF3. eRF1 recognizes stop signals, whereas eRF3 is a ribosome-dependent and eRFl-dependent GTPase. Polypeptide release factor eRF3 consists of N-terminal variable region and C-terminal conserved part. C-terminal part of eRF3 is responsible for termination of the translation, In the present study, the C-terminal of Euplotes octocarinatus eRF3 （eRF3C） and truncate eRF3C lacking 76 amino acids in C-terminal （eRF3Ct） were expressed in Escherichia coll. The recombinant GST-eRF3C and GST-eRF3Ct polypeptides were purifled by affinity chromatography using glutathione Sepharose 4B column. After enzymatic cleavage of GST tail, the eRF3C and eRF3Ct protein were obtained. Pull-down analysis showed that the recombinant GST-eRF3C and GST-eRF3Ct polypeptides interacted with E. octocarinatus polypeptide chain release factor eRF1a. This result suggested that the C-terminal of eRF3 having 76 amino acids were not required for the binding of eRFla in Euplotes octocarinatus.展开更多
AIM: To assess the impact of eukaryotic elongation factor 1 alpha 2 (eEF1A2) on hepatocellular carcinoma (HCC) cell proliferation, apoptosis, migration and invasion, and determine the underlying mechanisms.METHODS: eE...AIM: To assess the impact of eukaryotic elongation factor 1 alpha 2 (eEF1A2) on hepatocellular carcinoma (HCC) cell proliferation, apoptosis, migration and invasion, and determine the underlying mechanisms.METHODS: eEF1A2 levels were detected in 62 HCC tissue samples and paired pericarcinomatous specimens, and the human HCC cell lines SK-HEP-1, HepG2 and BEF-7402, by real-time PCR and immunohistochemistry. Experimental groups included eEF1A2 silencing in BEL-7402 cells with lentivirus eEF1A2-shRNA (KD group) and eEF1A2 overexpression in SK-HEP-1 cells with eEF1A2 plasmid (OE group). Non-transfected cells (control group) and lentivirus-based empty vector transfected cells (NC group) were considered control groups. Cell proliferation (MTT and colony formation assays), apoptosis (Annexin V-APC assay), cell cycle (DNA ploidy assay), and migration and invasion (Transwell assays) were assessed. Protein levels of PI3K/Akt/NF-κB signaling effectors were evaluated by Western blot.RESULTS: eEF1A2 mRNA and protein levels were significantly higher in HCC cancer tissue samples than in paired pericarcinomatous and normal specimens. SK-HEP-1 cells showed lower eEF1A2 mRNA levels; HepG2 and BEL-7402 cells showed higher eEF1A2 mRNA levels, with BEL-7402 cells displaying the highest amount. Efficient eEF1A2 silencing resulted in reduced cell proliferation, migration and invasion, increased apoptosis, and induced cell cycle arrest. The PI3K/Akt/NF-κB signaling pathway was notably inhibited. Inversely, eEF1A2 overexpression resulted in promoted cell proliferation, migration and invasion.CONCLUSION: eEF1A2, highly expressed in HCC, is a potential oncogene. Its silencing significantly decreases HCC tumorigenesis, likely by inhibiting PI3K/Akt/NF-κB signaling.展开更多
Objective To analyze the relationship between malignant transformation and abnormal expression of eukaryotic initiation factor 3 （eIF3 p36） in human bronchial epithelial （16HBE） cells induced by cadmium chloride ...Objective To analyze the relationship between malignant transformation and abnormal expression of eukaryotic initiation factor 3 （eIF3 p36） in human bronchial epithelial （16HBE） cells induced by cadmium chloride （CdCl2）. Methods 16HBE cells were treated several times with different concentrations of CdCl2. Tumorigenic potential of transformed cells was identified by assays for anchorage-independent growth in soft agar and for tumorigenicity in nude mice after the 35th passage. Total RNA was isolated from 16HBE cells induced by CdC12, including non-transformed, Cd-transformed, and Cd-tumorigenic cell lines. Special primers for eIF3 p36 were designed and the expression of eIF3 mRNA in different cell lines was detected with fluorescent quantitative-polymerase chain reaction technique （FQ-PCR）. Results The 35th passage of 16HBE cells transformed by CdCl2 exhibited overlapping growth. Compared with the non-transformed cells, colonies of transformed cell lines in soft agar showed statistically significant increases and dose-dependent effects （P〈0.01）. All Cd-induced transformed cell lines formed rumors in nude mice within 2 weeks of inoculation, but none of the mice injected with non-transformed cells showed tumors even after 3 weeks. All tumors were pathologically identified as poorly differentiated squamous cell carcinoma. The eIF3 p36 genes in different stages of 16HBE cells transformed by CdCl2 were elevated as compared with the non-transformed control （P〈0.01）, and the eIF3 expression increased with the degree of cell malignancy. Conclusion CdCl2 is capable of inducing morphological transformation in 16HBE cells and transformed cells are potentially tumorigenic. Over-expression of eIF3 p36 is positively correlated with malignant transformation of 16HBE cells induced by CdCl2 and may be one of the molecular mechanisms potentially responsible for carcinogenesis due to Cd.展开更多
Viruses are representative of a global threat to agricultural production. Genetic resistance is the preferred strategy for the control of viral infection and against loss of crop yield. Viral protein synthesis require...Viruses are representative of a global threat to agricultural production. Genetic resistance is the preferred strategy for the control of viral infection and against loss of crop yield. Viral protein synthesis requires host cellular factors for translating their viral RNAs, and for regulating their replication and cell to cell systemic movement. Therefore, the viruses are dependent on cellular translation factors. Mutations in the gene encoding eIF4E and eIF4G or their isoforms, eIFiso4 E, eIFiso4 G and eIF2Bβ have been mapped as a source of plant potyvirus while other genus of plant virus recessive resistance genes in many species are originated from these loci. Some of other plant translation factors, such as eIF3,eIF4 A-like helicases, eEF1A and eEF1B, which are required in interacting with viral RNAs and regulating various aspects of the infection cycle,have also been identified. Here, we summarized the mechanisms utilized by RNA viruses of eukaryotic plants and the essential roles of e IFs in virus infection. Moreover, we discussed the potential of e IFs as a target gene in the development of genetic resistance to viruses for crop improvement. This review highlighted newly revealed examples of abnormal translational strategies and provided insights into natural host resistance mechanisms that have been linked to 3 cap-independent translational enhancer activity.展开更多
Objective:The eukaryotic release factor 3a(eRF3a),a member of the eukaryotic peptide chain release factor family,is overexpressed in several types of cancer.This study aims to investigate the biological role and mecha...Objective:The eukaryotic release factor 3a(eRF3a),a member of the eukaryotic peptide chain release factor family,is overexpressed in several types of cancer.This study aims to investigate the biological role and mechanism of eRF3a in the progression of liver cancer.展开更多
基金This work was supported by grants from National Natural Science Foundation of China(No.30670282,30470239,3030038)Natural Science Foundation of Shanxi Province(No.20041079,20051065).
文摘Termination of translation in eukaryotes requires two polypeptide chain-release factors, eRF1 and eRF3. eRF1 recognizes stop signals, whereas eRF3 is a ribosome-dependent and eRFl-dependent GTPase. Polypeptide release factor eRF3 consists of N-terminal variable region and C-terminal conserved part. C-terminal part of eRF3 is responsible for termination of the translation, In the present study, the C-terminal of Euplotes octocarinatus eRF3 （eRF3C） and truncate eRF3C lacking 76 amino acids in C-terminal （eRF3Ct） were expressed in Escherichia coll. The recombinant GST-eRF3C and GST-eRF3Ct polypeptides were purifled by affinity chromatography using glutathione Sepharose 4B column. After enzymatic cleavage of GST tail, the eRF3C and eRF3Ct protein were obtained. Pull-down analysis showed that the recombinant GST-eRF3C and GST-eRF3Ct polypeptides interacted with E. octocarinatus polypeptide chain release factor eRF1a. This result suggested that the C-terminal of eRF3 having 76 amino acids were not required for the binding of eRFla in Euplotes octocarinatus.
基金Supported by the Middle-Young Age Backbone Talent Cultivation Program of Fujian Health System,No.2013-ZQNJC-2Key Projects of Science and Technology Plan of Fujian Province,No.2014Y0009
文摘AIM: To assess the impact of eukaryotic elongation factor 1 alpha 2 (eEF1A2) on hepatocellular carcinoma (HCC) cell proliferation, apoptosis, migration and invasion, and determine the underlying mechanisms.METHODS: eEF1A2 levels were detected in 62 HCC tissue samples and paired pericarcinomatous specimens, and the human HCC cell lines SK-HEP-1, HepG2 and BEF-7402, by real-time PCR and immunohistochemistry. Experimental groups included eEF1A2 silencing in BEL-7402 cells with lentivirus eEF1A2-shRNA (KD group) and eEF1A2 overexpression in SK-HEP-1 cells with eEF1A2 plasmid (OE group). Non-transfected cells (control group) and lentivirus-based empty vector transfected cells (NC group) were considered control groups. Cell proliferation (MTT and colony formation assays), apoptosis (Annexin V-APC assay), cell cycle (DNA ploidy assay), and migration and invasion (Transwell assays) were assessed. Protein levels of PI3K/Akt/NF-κB signaling effectors were evaluated by Western blot.RESULTS: eEF1A2 mRNA and protein levels were significantly higher in HCC cancer tissue samples than in paired pericarcinomatous and normal specimens. SK-HEP-1 cells showed lower eEF1A2 mRNA levels; HepG2 and BEL-7402 cells showed higher eEF1A2 mRNA levels, with BEL-7402 cells displaying the highest amount. Efficient eEF1A2 silencing resulted in reduced cell proliferation, migration and invasion, increased apoptosis, and induced cell cycle arrest. The PI3K/Akt/NF-κB signaling pathway was notably inhibited. Inversely, eEF1A2 overexpression resulted in promoted cell proliferation, migration and invasion.CONCLUSION: eEF1A2, highly expressed in HCC, is a potential oncogene. Its silencing significantly decreases HCC tumorigenesis, likely by inhibiting PI3K/Akt/NF-κB signaling.
基金the National Natural Science Foundation of China (No. 30371195)Guangdong NaturalScience Foundation (No. 06022672)+1 种基金Guangzhou Science and Technology Foundation (No. 2003Z2-E0191/E0192)Guangzhou Municipal Department of Education (No. 1002)
文摘Objective To analyze the relationship between malignant transformation and abnormal expression of eukaryotic initiation factor 3 （eIF3 p36） in human bronchial epithelial （16HBE） cells induced by cadmium chloride （CdCl2）. Methods 16HBE cells were treated several times with different concentrations of CdCl2. Tumorigenic potential of transformed cells was identified by assays for anchorage-independent growth in soft agar and for tumorigenicity in nude mice after the 35th passage. Total RNA was isolated from 16HBE cells induced by CdC12, including non-transformed, Cd-transformed, and Cd-tumorigenic cell lines. Special primers for eIF3 p36 were designed and the expression of eIF3 mRNA in different cell lines was detected with fluorescent quantitative-polymerase chain reaction technique （FQ-PCR）. Results The 35th passage of 16HBE cells transformed by CdCl2 exhibited overlapping growth. Compared with the non-transformed cells, colonies of transformed cell lines in soft agar showed statistically significant increases and dose-dependent effects （P〈0.01）. All Cd-induced transformed cell lines formed rumors in nude mice within 2 weeks of inoculation, but none of the mice injected with non-transformed cells showed tumors even after 3 weeks. All tumors were pathologically identified as poorly differentiated squamous cell carcinoma. The eIF3 p36 genes in different stages of 16HBE cells transformed by CdCl2 were elevated as compared with the non-transformed control （P〈0.01）, and the eIF3 expression increased with the degree of cell malignancy. Conclusion CdCl2 is capable of inducing morphological transformation in 16HBE cells and transformed cells are potentially tumorigenic. Over-expression of eIF3 p36 is positively correlated with malignant transformation of 16HBE cells induced by CdCl2 and may be one of the molecular mechanisms potentially responsible for carcinogenesis due to Cd.
基金The authors thank Mr.Tomas Maher from the Department of Biology at the Pennsylvania State University for language editing.This work is supported by the National Natural Science Foundation of Zhejiang Province(Grant No.LZ20C150002)and the National Natural Science Foundation of China(Grant No.31872095).
文摘Viruses are representative of a global threat to agricultural production. Genetic resistance is the preferred strategy for the control of viral infection and against loss of crop yield. Viral protein synthesis requires host cellular factors for translating their viral RNAs, and for regulating their replication and cell to cell systemic movement. Therefore, the viruses are dependent on cellular translation factors. Mutations in the gene encoding eIF4E and eIF4G or their isoforms, eIFiso4 E, eIFiso4 G and eIF2Bβ have been mapped as a source of plant potyvirus while other genus of plant virus recessive resistance genes in many species are originated from these loci. Some of other plant translation factors, such as eIF3,eIF4 A-like helicases, eEF1A and eEF1B, which are required in interacting with viral RNAs and regulating various aspects of the infection cycle,have also been identified. Here, we summarized the mechanisms utilized by RNA viruses of eukaryotic plants and the essential roles of e IFs in virus infection. Moreover, we discussed the potential of e IFs as a target gene in the development of genetic resistance to viruses for crop improvement. This review highlighted newly revealed examples of abnormal translational strategies and provided insights into natural host resistance mechanisms that have been linked to 3 cap-independent translational enhancer activity.
基金This work was supported by grants from the National Natural Science Foundation of China(No.81770283,No.81902018 and No.82070302)。
文摘Objective:The eukaryotic release factor 3a(eRF3a),a member of the eukaryotic peptide chain release factor family,is overexpressed in several types of cancer.This study aims to investigate the biological role and mechanism of eRF3a in the progression of liver cancer.
