Inducible Expression of Translation Elongation Factor 1A Gene in Rice Seedlings in Response to Environmental Stresses

Differences of gene expression between salinity_stressed and control rice ( Oryza sativa L. ssp. indica ) cultivar “Zhaiyeqing 8' were compared using differential display PCR (DD_PCR) technique. Sequence analysis of one salt_inducible cDNA clone revealed that this clone represented a new member of rice translation elongation factor 1A (eEF1A) gene family and was tentatively named REF1A. Northern blot hybridization using REF1A fragment as a probe was performed to investigate the expression of rice translation elongation factor 1A gene in response to various environmental factors. It was observed that expression of the eEF1A gene in rice shoots was dramatically induced by salinity stress or exogenous application of abscisic acid (ABA). The induction of this gene by ABA stress occurred more quickly than that by salinity stress. In addition, expression of rice translation elongation factor 1A gene was also induced by drought (15% PEG6000), cold (4 ℃) or heat_shock (37 ℃) stresses. The results suggested that the induction of translation elongation factor 1A gene expression by environmental stresses might reflect the general adaptive response of rice plants to the adverse circumstances.

Eukaryotic elongation factor-1α 2 knockdown inhibits hepatocarcinogenesis by suppressing PI3K/Akt/NF-κB signaling

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.

Enhancement of innate immune system in monocot rice by transferring the dicotyledonous elongation factor Tu receptor EFR

The elongation factor Tu （EF-Tu） receptor （EFR） in cruciferous plants specifically recognizes the N-terminal acetylated elf18 region of bacterial EF-Tu and thereby activates plant immunity. It has been demonstrated that Arabidopsis EFR confers broad-spectrum bacterial resistance in the EFR transgenic solanaceous plants. Here, the transgenic rice plants （Oryza sativa L. ssp. japonica cv. Zhonghua 17） and cell cultures with constitutive expression of AtEFR were developed to investigate whether AtEFR senses EF-Tu and thus enhances bacterial resistance in the monocot plants. We＇demonstrated that the Xanthomonas oryzae-derived elf18 peptide induced oxidative burst and mitogen-activated protein kinase activa- tion in the AtEFR transgenic rice cells and plants, respectively. Pathogenesis-related genes, such as OsPBZ1, were upregulated dramatically in transgenic rice plant and cell lines in response to elf18 stimulation. Importantly, pretreatment with elf18 trig- gered strong resistance to X. oryzae pv. oryzae in the transgenic plants, which was largely dependent on the AtEFR expressionlevel. These plants also exhibited enhanced resistance to rice bacterial brown stripe, but not to rice fungal blast. Collectively, the results indicate that the rice plants with heterologous expression of AtEFR recognize bacterial EF-Tu and exhibit enhanced broad-spectrum bacterial disease resistance and that pattern recognition receptor-mediated immunity may be manipulated across the two plant classes, dicots and monocots.

The pseudogenes of eukaryotic translation elongation factors (EEFs): Role in cancer and other human diseases

The eukaryotic translation elongation factors (EEFs), i.e. EEF1A1, EEF1A2, EEF1B2, EEF1D, EEF1G, EEF1E1 and EEF2, are coding-genes that play a central role in the elongation step of translation but are often altered in cancer. Less investigated are their pseudogenes. Recently, it was demonstrated that pseudogenes have a key regulatory role in the cell, especially via non-coding RNAs, and that the aberrant expression of ncRNAs has an important role in cancer development and progression. The present review paper, for the first time, collects all that published about the EEFs pseudogenes to create a base for future investigations. For most of them, the studies are in their infancy, while for others the studies suggest their involvement in normal cell physiology but also in various human diseases. However, more investigations are needed to understand their functions in both normal and cancer cells and to define which can be useful biomarkers or therapeutic targets.

Roles of eEF-2 kinase in cancer

Objective To provide a summary of the relationship between the eEF-2/eEF-2 kinase pathway and each phase of malignant neoplasms. The specific importance of this relationship in understanding and treating cancer was also explored. Data sources The data used in this review were mainly obtained from the articles listed in HighWire and PubMed in English. The search terms were ＂eEF-2 kinase＂, ＂oncogenesis＂, and ＂tumor progression＂. Study selection This review relates the observation that the overexpression of eEF-2 kinase is seen in cancer, and highlights that it has emerged as promoting the development of many malignant phenotypes when unregulated. This includes increasing the replicative potential of cells, angiogenesis, invasion and metastasis, and evasion of apoptosis. Results eEF-2 kinase is a structurally and functionally unique protein kinase. The increased activity of this protein in cancer cells is a protective mechanism to allow tumor growth and evolution, and resist cell death through the eEF-2/eEF-2 kinase pathway, but it also makes a potential target for therapy. Conclusion eEF-2 kinase fills critical niches in the life of a cancer cell and the eEF-2/eEF-2 kinase pathway is a key biochemical sensor.

Sequence data reveal a high diversity of Cantharellus associated with endemic vegetation in Madagascar

This revision of Cantharellus in Madagascar deals with species that are associated with strictly endemic host trees and shrubs.Based on morphological differences and molecular sequence data of the tef-1 gene,five new species are proposed(C.albidolutescens,C.ambohitantelyensis,C.ibityensis,C.paucifurcatus and C.sebosus),as well as one new subspecies,C.subincarnatus ssp.rubrosalmoneus,whereas C.decolorans and C.platyphyllus ssp.bojeriensis are epitypified.A key is provided to all Cantharellus that grow with native vegetation in Madagascar.

Integrative proteomics reveals the role of E3 ubiquitin ligase SYVN1 in hepatocellular carcinoma metastasis

Background:Tumor metastasis is a major factor for poor prognosis of hepatocellular carcinoma(HCC),but the relationship between ubiquitination and metastasis need to be studiedmore systematically.We analyzed the ubiquitinome of HCC in this study to have a more comprehensive insight into human HCC metastasis.Methods:The protein ubiquitination levels in 15 HCC specimens with vascular invasion and 15 without vascular invasion were detected by ubiquitinome.Proteins with significantly different ubiquitination levels between HCCs with and without vascular invasion were used to predict E3 ubiquitin ligases associated with tumor metastasis.The topological network of protein substrates and corresponding E3 ubiquitin ligaseswas constructed to identify the key E3 ubiquitin ligase.Besides,the growth,migration and invasion ability of LM3 and HUH7 hepatoma cell lines with andwithout SYVN1 expression interferencewere measured by cell proliferation assay,subcutaneous tumor assay,umphal vein endothelium tube formation assay,transwell migration and invasion assays.Finally,the interacting proteins of SYVN1 were screened and verified by protein interaction omics,immunofluorescence,and immunoprecipitation.Ubiquitin levels of related protein substrates in LM3 and HUH7 cells were compared in negative control,SYVN1 knockdown,and SYVN1 overexpression groups.Results:In this study,our whole-cell proteomic dataset and ubiquitinomic dataset contained approximately 5600 proteins and 12,000 ubiquitinated sites.We discovered increased ubiquitinated sites with shorter ubiquitin chains during the progression ofHCC metastasis.In addition,proteomic and ubiquitinomic analyses revealed that high expression of E3 ubiquitin-protein ligase SYVN1 is related with tumor metastasis.Furthermore,we found that SYVN1 interacted with heat shock protein 90(HSP90)and impacted the ubiquitination of eukaryotic elongation factor 2 kinase(EEF2K).Conclusions:The ubiquitination profiles of HCC with and without vascular invasion were significantly different.SYVN1 was the most important E3 ubiquitin-protein ligase responsible for this phenomenon,and itwas related with tumormetastasis and growth.Therefore,SYVN1might be a potential therapeutic target for HCC.