Elongation factor 1A1 regulates metabolic substrate preference in mammalian cells

Eukaryotic elongation factor 1A1 (EEF1A1) is canonically involved in protein synthesis but also has noncanonical functions in diverse cellular processes. Previously, we identified EEF1A1 as a mediator of lipotoxicity and demonstrated that chemical inhibition of EEF1A1 activity reduced mouse liver lipid accumulation. These findings suggested a link between EEF1A1 and metabolism. Therefore, we investigated its role in regulating metabolic substrate preference. EEF1A1-deficient Chinese hamster ovary (2E2) cells displayed reduced media lactate accumulation. These effects were also observed with EEF1A1 knockdown in human hepatocyte-like HepG2 cells and in WT Chinese hamster ovary and HepG2 cells treated with selective EEF1A inhibitors, didemnin B, or plitidepsin. Extracellular flux analyses revealed decreased glycolytic ATP production and increased mitochondrial-to-glycolytic ATP production ratio in 2E2 cells, suggesting a more oxidative metabolic phenotype. Correspondingly, fatty acid oxidation was increased in 2E2 cells. Both 2E2 cells and HepG2 cells treated with didemnin B exhibited increased neutral lipid content, which may be required to support elevated oxidative metabolism. RNA-seq revealed a >90-fold downregulation of a rate-limiting glycolytic enzyme, hexokinase 2, which we confirmed through immunoblotting and enzyme activity assays. Pathway enrichment analysis identified downregulations in TNFA signaling via NFKB and MYC targets. Correspondingly, nuclear abundances of RELB and MYC were reduced in 2E2 cells. Thus, EEF1A1 deficiency may perturb glycolysis by limiting NFKB- and MYC-mediated gene expression, leading to decreased hexokinase expression and activity. This is the first evidence of a role for a translation elongation factor, EEF1A1, in regulating metabolic substrate utilization in mammalian cells.

Evaluation of Suitable Reference Genes for Quantitative Real-Time PCR in Various Tissues of Apocynum venetum

Apocynum venetum L. is an economically valuable plant with tolerance to drought and salinity. Its leaves are utilized in tea production and pharmaceuticals, while the stem bark serves as a high-quality fiber material. To gain insights into the gene expression patterns of A. venetum using quantitative real-time PCR (qRT-PCR), it is crucial to identify appropriate reference genes. This study selected nine candidate genes, including α-tubulin (TUA), β-tubulin (TUB), actin (ACT), cyclophilin (CYP), elongation factor-1α (EF-1α), the B family of regulatory subunits of protein phosphatase (PPP2R2, PPP2R3, and PPP2R5), and phosphoglycerate kinase (PGK), to determine the most appropriate reference genes in the leaf, stem, and root tissues of A. venetum. A comprehensive ranking by geNorm, NormFinder, BestKeeper, and RefFinder software and Venn diagrams was used to screen more stable reference genes in different tissues. The two most stable reference genes were CYP and TUA in leaves, PGK and PPP2R3 in stems, and TUA and EF-1α in roots, respectively. The relative expression values of the four genes involved in proline metabolism under polyethylene glycol treatment were used to validate the screened reference genes, and they exhibited highly stable expression levels. These findings represent the first set of stable reference genes for future gene expression studies in A. venetum. They significantly contribute to enhancing the accuracy and reliability of gene expression analyses in this economically important plant species.

Methylation of elongation factor 1A by yeast Efm4 or human eEF1A-KMT2 involves a beta-hairpin recognition motif and crosstalks with phosphorylation

Translation elongation factor 1A (eEF1A) is an essential and highly conserved protein required for protein synthesis in eukaryotes. In both Saccharomyces cerevisiae and human, five different methyltransferases methylate specific residues on eEF1A, making eEF1A the eukaryotic protein targeted by the highest number of dedicated methyltransferases after histone H3. eEF1A methyltransferases are highly selective enzymes, only targeting eEF1A and each targeting just one or two specific residues in eEF1A. However, the mechanism of this selectivity remains poorly understood. To reveal how S. cerevisiae elongation factor methyltransferase 4 (Efm4) specifically methylates eEF1A at K316, we have used AlphaFold-Multimer modeling in combination with crosslinking mass spectrometry (XL-MS) and enzyme mutagenesis. We find that a unique beta-hairpin motif, which extends out from the core methyltransferase fold, is important for the methylation of eEF1A K316 in vitro. An alanine mutation of a single residue on this beta-hairpin, F212, significantly reduces Efm4 activity in vitro and in yeast cells. We show that the equivalent residue in human eEF1A-KMT2 (METTL10), F220, is also important for its activity towards eEF1A in vitro. We further show that the eEF1A guanine nucleotide exchange factor, eEF1Bα, inhibits Efm4 methylation of eEF1A in vitro, likely due to competitive binding. Lastly, we find that phosphorylation of eEF1A at S314 negatively crosstalks with Efm4-mediated methylation of K316. Our findings demonstrate how protein methyltransferases can be highly selective towards a single residue on a single protein in the cell.

Ogataea nonmethanolica f.a, sp. nov., a novel yeast species isolated from rotting wood in Brazil and Colombia

Three yeast isolate candidates for a novel species were obtained from rotting wood samples collected in Brazil and Colombia. The Brazilian isolate differs from the Colombian isolates by one nucleotide substitution in each of the D1/D2 and small subunit (SSU) sequences. The internal transcribed spacer (ITS) and translation elongation factor 1-α gene sequences of the three isolates were identical. A phylogenetic analysis showed that this novel species belongs to the genus Ogataea. This novel species is phylogenetically related to Candida nanaspora and Candida nitratophila. The novel species differs from C. nanaspora by seven nucleotides and two indels, and by 17 nucleotides and four indels from C. nitratophila in the D1/D2 sequences. The ITS sequences of these three species differ by more than 30 nucleotides. Analyses of the sequences of the SSU and translation elongation factor 1-α gene also showed that these isolates represent a novel species of the genus Ogataea. Different from most Ogataea species, these isolates did not assimilate methanol as the sole carbon source. The name Ogataea nonmethanolica sp. nov. is proposed to accommodate these isolates. The holotype of Ogataea nonmethanolica is CBS 13485T. The MycoBank number is MB 851195.

EEF1A2 promotes HIF1A mediated breast cancer angiogenesis in normoxia and participates in a positive feedback loop with HIF1A in hypoxia

BACKGROUND

The eukaryotic elongation factor, EEF1A2, has been identified as an oncogene in various solid tumors. Here, we have identified a novel function of EEF1A2 in angiogenesis.

METHODS

Chick chorioallantoic membrane, tubulogenesis, aortic ring, Matrigel plug, and skin wound healing assays established EEF1A2's role in angiogenesis.

RESULT

Higher EEF1A2 levels in breast cancer cells enhanced cell growth, movement, blood vessel function, and tubule formation in HUVECs, as confirmed by ex-ovo and in-vivo tests. The overexpression of EEF1A2 could be counteracted by Plitidepsin. Under normoxic conditions, EEF1A2 triggered HIF1A expression via ERK-Myc and mTOR signaling in TNBC and ER/PR positive cells. Hypoxia induced the expression of EEF1A2, leading to a positive feedback loop between EEF1A2 and HIF1A. Luciferase assay and EMSA confirmed HIF1A binding on the EEF1A2 promoter, which induced its transcription. RT-PCR and polysome profiling validated that EEF1A2 affected VEGF transcription and translation positively. This led to increased VEGF release from breast cancer cells, activating ERK and PI3K-AKT signaling in endothelial cells. Breast cancer tissues with elevated EEF1A2 showed higher microvessel density.

CONCLUSION

EEF1A2 exhibits angiogenic potential in both normoxic and hypoxic conditions, underscoring its dual role in promoting EMT and angiogenesis, rendering it a promising target for cancer therapy.

Oncogenic activation of EEF1A2 expression: a journey from a putative to an established oncogene

Protein synthesis via translation is a central process involving several essential proteins called translation factors. Although traditionally described as cellular "housekeepers," multiple studies have now supported that protein initiation and elongation factors regulate cell growth, apoptosis, and tumorigenesis. One such translation factor is eukaryotic elongation factor 1 alpha 2 (EEF1A2), a member of the eukaryotic elongation factor family, which has a canonical role in the delivery of aminoacyl-tRNA to the A-site of the ribosome in a guanosine 5'-triphosphate (GTP)-dependent manner. EEF1A2 differs from its closely related isoform, EEF1A1, in tissue distribution. While EEF1A1 is present ubiquitously, EEF1A2 replaces it in specialized tissues. The reason why certain specialized tissues need to essentially switch EEF1A1 expression altogether with EEF1A2 remains to be answered. Abnormal "switch on" of the EEF1A2 gene in normal tissues is witnessed and is seen as a cause of oncogenic transformation in a wide variety of solid tumors. This review presents the journey of finding increased expression of EEF1A2 in multiple cancers, establishing molecular mechanism, and exploring it as a target for cancer therapy. More precisely, we have compiled studies in seven types of cancers that have reported EEF1A2 overexpression. We have discussed the effect of aberrant EEF1A2 expression on the oncogenic properties of cells, signaling pathways, and interacting partners of EEF1A2. More importantly, in the last part, we have discussed the unique potential of EEF1A2 as a therapeutic target. This review article gives an up-to-date account of EEF1A2 as an oncogene and can draw the attention of the scientific community, attracting more research.

Autosomal recessive intellectual disability caused by compound heterozygous variants of the EEF1D gene in a Chinese family

BACKGROUND

Intellectual disability is a prevalent neurodevelopmental disorder, with the majority of affected children exhibiting global developmental delay before the age of 5 years. In recent years, certain children have been found to carry homozygous variations of the EEF1D gene, leading to autosomal recessive intellectual disability. However, the pathogenicity of compound heterozygous variations in this gene remains largely unknown.

METHODS

Trio whole-exome sequencing and copy number variation sequencing were done for the genetic etiological diagnosis of a 3-year and 11-month-old Chinese boy who presented with brachycephaly, severe to profound global developmental delay, and hypotonia in the lower limbs.

RESULTS

In this case, compound heterozygous variants of the EEF1D gene were found in the child through trio whole-exome sequencing; one was a splice variant (NM_032378.6:c.1905+1G>A) inherited from his father, and the other was a nonsense variant (NM_032378.6:c.676C>T) inherited from his mother. The nonsense variant leads to the production of a premature termination (p.Gln226*). These variations have the ability to explain the clinical phenotypes of the child.

CONCLUSIONS

Our study expands the variation spectrum and provides compelling evidence for EEF1D as a candidate gene for autosomal recessive intellectual disability. However, due to the deficient number of reported cases, researchers need to further study EEF1D and supplement the clinical phenotypes and treatment measures.

[Role of Eukaryotic Translation Elongation Factor 1 Family Members in the Tumorigenesis and Progression of Lung Adenocarcinoma]

Objective To investigate the role and mechanism of eukaryotic translation elongation factor 1(EEF1) family members (EEF1D,EEF1A1,and EEF1A2) in lung adenocarcinoma (LUAD) based on public databases.Methods We examined EEF1 member expression levels in human LUAD samples via The Cancer Genome Atlas in the UCSC Xena browser and the Clinical Proteomic Tumor Analysis Consortium.We analyzed the mRNA and protein levels of EEF1D,EEF1A1,and EEF1A2 and their correlations with pathological variables via the Mann-Whitney U test.The Kaplan-Meier curves were established to assess the prognostic values of EEF1D,EEF1A1,and EEF1A2.The single-sample gene set enrichment analysis algorithm was employed to explore the relationship between the expression levels of EEF1 members and tumor immune cell infiltration.Spearman and Pearson correlation analyses were performed to examine the relationship between the expression levels of EEF1 members and those of the genes in the phosphatidylinositol 3-kinase/protein kinase B signaling pathway.The immunohistochemical assay was employed to determine the expression levels of EEF1D,EEF1A1,and EEF1A2 in the LUAD tissue (n=75) and paracancer tissue (n=75) samples.Results The mRNA and protein levels of EEF1D,EEF1A1,and EEF1A2 showed significant differences between tumor and paracancer tissues (all P<0.001).The patients with high protein levels of EEF1A1 showed bad prognosis in terms of overall survival (P=0.039),and those with high protein levels of EEF1A2 showed good prognosis in terms of overall survival (P=0.012).The influence of the mRNA level of EEF1D on prognosis was associated with pathological characteristics.The expression levels of EEF1 members were significantly associated with the infiltration of various immune cells and the expression of key molecules in the phosphatidylinositol 3-kinase/protein kinase B signaling pathway.Conclusion EEF1D,EEF1A1,and EEF1A2 are associated with the progression of LUAD,serving as the candidate prognostic markers for LUAD.

Expression profiles of oviductal mRNAs and lncRNAs in the follicular phase and luteal phase of sheep (Ovis aries) with 2 fecundity gene (FecB) genotypes

FecB (also known as BMPR1B) is a crucial gene in sheep reproduction, which has a mutation (A746G) that was found to increase the ovulation rate and litter size. The FecB mutation is associated with reproductive endocrinology, such mutation can control external estrous characteristics and affect follicle-stimulating hormone during the estrous cycle. Previous researches showed that the FecB mutation can regulate the transcriptomic profiles in the reproductive-related tissues including hypothalamus, pituitary, and ovary during the estrous cycle of small-tailed Han (STH) sheep. However, little research has been reported on the correlation between FecB mutation and the estrous cycle in STH sheep oviduct. To investigate the coding and noncoding transcriptomic profiles involved in the estrous cycle and FecB in the sheep oviduct, RNA sequencing was performed to analyze the transcriptomic profiles of mRNAs and long noncoding RNAs (lncRNAs) in the oviduct during the estrous cycle of STH sheep with mutant (FecBBB) and wild-type (FecB++) genotypes. In total, 21,863 lncRNAs and 43,674 mRNAs were screened, the results showed that mRNAs had significantly higher expression levels than the lncRNAs, and the expression levels of these screened transcripts were lower in the follicular phase than they were in the luteal phase. Among them, the oviductal glycoprotein gene (OVGP1) had the highest expression level. In the comparison between the follicular and luteal phases, 57 differentially expressed (DE) lncRNAs and 637 DE mRNAs were detected, including FSTL5 mRNA and LNC_016628 lncRNA. In the comparison between the FecBBB and FecB++ genotypes, 26 DE lncRNAs and 421 DE mRNAs were detected, including EEF1D mRNA and LNC_006270 lncRNA. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes functional enrichment analysis indicated that the DE mRNAs were enriched mainly in terms related to reproduction such as the tight junction, SAGA complex, ATP-binding cassette, nestin, and Hippo signaling pathway. The interaction network between DE lncRNAs and DE mRNAs indicated that LNC_018420 may be the key regulator in sheep oviduct. Together, our results can provide novel insights into the oviductal transcriptomic function against a FecB mutation background in sheep reproduction.

Eukaryotic translation elongation factor 1 alpha (eEF1A) inhibits Siniperca chuatsi rhabdovirus (SCRV) infection through two distinct mechanisms

IMPORTANCE

Although a virus can regulate many cellular responses to facilitate its replication by interacting with host proteins, the host can also restrict virus infection through these interactions. In the present study, we showed that the host eukaryotic translation elongation factor 1 alpha (eEF1A), an essential protein in the translation machinery, interacted with two proteins of a fish rhabdovirus, Siniperca chuatsi rhabdovirus (SCRV), and inhibited virus infection via two different mechanisms: (i) inhibiting the formation of crucial viral protein complexes required for virus transcription and replication and (ii) promoting the ubiquitin-proteasome degradation of viral protein. We also revealed the functional regions of eEF1A that are involved in the two processes. Such a host protein inhibiting a rhabdovirus infection in two ways is rarely reported. These findings provided new information for the interactions between host and fish rhabdovirus.

PCMT1 knockdown attenuates malignant properties by globally regulating transcriptome profiles in triple-negative breast cancer cells

Background

As the most frequently diagnosed cancer in women, Breast cancer has high mortality and metastasis rate, especially triple-negative breast cancer (TNBC). As an oncogene, protein-L-isoaspartate (D-aspartate) O-methyltransferase (PCMT1) is a prognostic biomarker in breast cancer and is highly expressed, while its underlying functions remain unknown.

Methods

In this study, we silenced PCTM1 in TNBC MDA-MB-231 cells by short hairpin RNA (shPCMT1) to investigate its cellular functions using cell proliferation, apoptosis, migration, and invasion experiments. Following this, the transcriptome sequencing (RNA-seq) experiment was conducted to explore the molecular targets of PCMT1, including differentially expressed genes (DEGs) and regulated alternative splicing events (RASEs).

Results

The results showed that shPCMT1 inhibited the proliferation, migration, and invasion of MDA-MB-231 cells. We obtained 1,084 DEGs and 2,287 RASEs between shPCMT1 and negative control (NC) groups through RNA-seq. The DEGs were significantly enriched in immune or inflammation response and cell adhesion-associated pathways, pathways associated with PCMT1 cellular function in cell migration. The RASE genes were enriched in cell cycle-associated pathways and were associated with the altered cell proliferation rate. We finally validated the changed expression and splicing levels of DEGs and RASEs. We found that 34 RNA binding protein (RBP) genes were dysregulated by shPCMT1, including NQO1, S100A4, EEF1A2, and RBMS2. The dysregulated RBP genes could partially explain how PCMT1 regulates the global transcriptome profiles.

Conclusion

In conclusion, our study identified the molecular targets of PCMT1 in the TNBC cell line, expands our understanding of the regulatory mechanisms of PCMT1 in cancer progression, and provides novel insights into the progression of TNBC. The identified molecular targets are potential therapeutic targets for future TNBC treatment.

Identification, molecular characterization, and antifungal susceptibility of Cyberlindnera fabianii strains isolated from urinary tract

OBJECTIVES

Cyberlindnera fabianii is an opportunistic pathogen isolated from clinical specimens. It can be incorrectly identified as Candida utulis by phenotypic methods. This study aimed to accurately identify Cy.fabianii strains isolated from the urinary tract, and to determine their molecular characterization and antifungal susceptibilities as well.

METHODS

Twenty-nine yeast strains isolated from urinary tract samples were studied. Strains were identified by phenotypically, sequence analysis and MALDI-TOF MS. Sequence analysis using different gene regions (ITS1-2,D1/D2,EF-1-alpha) in ribosomal DNA was performed for the molecular analysis. Phylogenetic analysis was done by the neighbor-joining method. Antifungal susceptibilities of strains were determined for nine antifungals by reference broth microdilution and the Sensititre YeastOne broth microdilution method (SensititreTMYeastOneTMAST Plate, Thermo Fisher Scientific™,USA) according to CLSI M60-Ed2 recommendations.

RESULTS

All strains were identified as C.utulis phenotypically by conventional methods, however all strains were identified as Cy.fabianii by sequence analysis and MALDI-TOF MS. It was observed that the gene regions examined in terms of determining evolutionary relatedness did not show intraspecies nucleotide variations. In all strains, the MIC50/MIC90 values for fluconazole were higher than the other antifungals tested.

CONCLUSION

Cy.fabianii should be considered in fluconazole-resistant urinary tract yeast infections. Although conventional phenotypical methods were insufficient to identify Cy.fabianii, it could be correctly identified with sequence analysis using different gene regions (ITS1-2,D1/D2,EF-1-alpha) in ribosomal DNA and MALDI-TOF MS.

Selection and validation of reliable reference genes for quantitative real-time PCR in Barnyard millet (Echinochloa spp.) under varied abiotic stress conditions

Quantitative real-time polymerase chain reaction (RT-qPCR) using a stable reference gene is widely used for gene expression research. Barnyard millet (Echinochloa spp.) is an ancient crop in Asia and Africa that is widely cultivated for food and fodder. It thrives well under drought, salinity, cold, and heat environmental conditions, besides adapting to any soil type. To date, there are no gene expression studies performed to identify the potential candidate gene responsible for stress response in barnyard millet, due to lack of reference gene. Here, 10 candidate reference genes, Actin (ACT), α-tubulin (α-TUB), β-tubulin (β-TUB), RNA pol II (RP II), elongation factor-1 alpha (EF-1α), adenine phosphoribosyltransferase (APRT), TATA-binding protein-like factor (TLF), ubiquitin-conjugating enzyme 2 (UBC2), ubiquitin-conjugating enzyme E2L5 (UBC5) and glyceraldehyde-3-phosphate dehydrogenase (GAPDH), were selected from mRNA sequences of E. crus-galli and E. colona var frumentacea. Five statistical algorithms (geNorm, NormFinder, BestKeeper, ΔCt, and RefFinder) were applied to determine the expression stabilities of these genes in barnyard millet grown under four different abiotic stress (drought, salinity, cold and heat) exposed at different time points. The UBC5 and ɑ-TUB in drought, GAPDH in salinity, GAPDH and APRT in cold, and EF-1α and RP II in heat were the most stable reference genes, whereas ß-TUB was the least stable irrespective of stress conditions applied. Further Vn/Vn + 1 analysis revealed two reference genes were sufficient to normalize gene expression across all sample sets. The suitability of identified reference genes was validated with Cu-ZnSOD (SOD1) in the plants exposed to different abiotic stress conditions. The results revealed that the relative quantification of the SOD1 gene varied according to reference genes and the number of reference genes used, thus highlighting the importance of the choice of a reference gene in such experiments. This study provides a foundational framework for standardizing RT-qPCR analyses, enabling accurate gene expression profiling in barnyard millet.

Autism- and epilepsy-associated EEF1A2 mutations lead to translational dysfunction and altered actin bundling

Protein synthesis is a fundamental cellular process in neurons that is essential for synaptic plasticity and memory consolidation. Here, we describe our investigations of a neuron- and muscle-specific translation factor, eukaryotic Elongation Factor 1a2 (eEF1A2), which when mutated in patients results in autism, epilepsy, and intellectual disability. We characterize three EEF1A2 patient mutations, G70S, E122K, and D252H, and demonstrate that all three mutations decrease de novo protein synthesis and elongation rates in HEK293 cells. In mouse cortical neurons, the EEF1A2 mutations not only decrease de novo protein synthesis but also alter neuronal morphology, regardless of endogenous levels of eEF1A2, indicating that the mutations act via a toxic gain of function. We also show that eEF1A2 mutant proteins display increased tRNA binding and decreased actin-bundling activity, suggesting that these mutations disrupt neuronal function by decreasing tRNA availability and altering the actin cytoskeleton. More broadly, our findings are consistent with the idea that eEF1A2 acts as a bridge between translation and the actin cytoskeleton, which is essential for proper neuron development and function.

Endogenous epitope tagging of eEF1A2 in mice reveals early embryonic expression of eEF1A2 and subcellular compartmentalisation of neuronal eEF1A1 and eEF1A2

All vertebrate species express two independently-encoded forms of translation elongation factor eEF1A. In humans and mice eEF1A1 and eEF1A2 are 92 % identical at the amino acid level, but the well conserved developmental switch between the two variants in specific tissues suggests the existence of important functional differences. Heterozygous mutations in eEF1A2 result in neurodevelopmental disorders in humans; the mechanism of pathogenicity is unclear, but one hypothesis is that there is a dominant negative effect on eEF1A1 during development. The high degree of similarity between the eEF1A proteins has complicated expression analysis in the past; here we describe a gene edited mouse line in which we have introduced a V5 tag in the gene encoding eEF1A2. Expression analysis using anti-V5 and anti-eEF1A1 antibodies demonstrates that, in contrast to the prevailing view that eEF1A2 is only expressed postnatally, it is expressed from as early as E11.5 in the developing neural tube. Two colour immunofluorescence also reveals coordinated switching between eEF1A1 and eEF1A2 in different regions of postnatal brain. Completely reciprocal expression of the two variants is seen in post-weaning mouse brain with eEF1A1 expressed in oligodendrocytes and astrocytes and eEF1A2 in neuronal soma. Although eEF1A1 is absent from neuronal cell bodies after development, it is widely expressed in axons. This expression does not appear to coincide with myelin sheaths originating from oligodendrocytes but rather results from localised translation within the axon, suggesting that both variants are transcribed in neurons but show completely distinct subcellular localisation at the protein level. These findings will form an underlying framework for understanding how missense mutations in eEF1A2 result in neurodevelopmental disorders.

EEF1A1 is Involved the Regulating Neuroinflammatory Processes in Parkinson's Disease

BACKGROUND

Studies have reported that the RNA-binding protein Eukaryotic Elongation Factor 1A1 (EEF1A1) is low expressed in the hippocampal region of Alzheimer's disease (AD). In addition, it is related to PARK2 activity in cells, predicting its importance in neurodegenerative diseases. However, the function of EEF1A1 in Parkinson's disease (PD) is unclear. Our study's primary objective was to knock down EEF1A1 in U251 cells and preliminarily explore the role of EEF1A1 in PD neuroinflammation.

METHODS

To inhibit EEF1A1 from being expressed in U251 cells, siRNA was transfected into those cells. Then, RNA-seq sequencing was used to determine the Differentially Expressed Genes (DEGs) resulting from the EEF1A1 knockdown. Additionally, gene ontology (GO) and kyoto encyclopedia of genes and genomes (KEGG) enrichment analyses were performed to find the biological processes and signaling pathways engaged in the DEGs, as well as to screen for genes associated with neuroinflammatory processes that influence the development of PD. Further Real Time - quantitative Polymerase Chain Reaction (RT-qPCR) validation experiments were performed to confirm the reliability of the sequencing results. Finally, combined with the support of related literature, the molecular mechanism of EEF1A1 in regulating the neuroinflammatory process of PD was initially explored.

RESULTS

Analysis using the RNA-seq technique showed that EEF1A1 knockdown could significantly upregulate the expression of IL-6, GDF15, STC1, MT1E, GPNMB, CCL5, MT1X, A2M, and VIP genes at the transcriptional level. These nine highly elevated genes were enriched to signaling pathways linked to inflammatory processes, according to an analysis of GO and KEGG enrichment.

CONCLUSIONS

EEF1A1 is involved in the regulating of IL-6, GDF15, STC1, MT1E, GPNMB, CCL5, MT1X, A2M, and VIP genes associated with the neuroinflammatory process of PD. Among them, we found that GDF15, STC1, MT1E, MT1X, GPNMB, VIP, and A2M genes were involved in delaying the neuroinflammatory process of PD, while IL-6 and CCL5 were involved in exacerbating the neuroinflammatory process, implicating that EEF1A1 may participate in the regulation of the PD neuroinflammation.

Increased prime edit rates in KCNQ2 and SCN1A via single nicking all-in-one plasmids

BACKGROUND

Prime editing (PE) is the most recent gene editing technology able to introduce targeted alterations to the genome, including single base pair changes, small insertions, and deletions. Several improvements to the PE machinery have been made in the past few years, and these have been tested in a range of model systems including immortalized cell lines, stem cells, and animal models. While double nicking RNA (dncRNA) PE systems PE3 and PE5 currently show the highest editing rates, they come with reduced accuracy as undesired indels or SNVs arise at edited loci. Here, we aimed to improve single ncRNA (sncRNA) systems PE2 and PE4max by generating novel all-in-one (pAIO) plasmids driven by an EF-1α promoter, which is especially suitable for human-induced pluripotent stem cell (hiPSC) models.

RESULTS

pAIO-EF1α-PE2 and pAIO-EF1α-PE4max were used to edit the voltage gated potassium channel gene KCNQ2 and voltage gated sodium channel gene SCN1A. Two clinically relevant mutations were corrected using pAIO-EF1α-PE2 including the homozygous truncating SCN1A R612* variant in HEK293T cells and the heterozygous gain-of-function KCNQ2 R201C variant in patient-derived hiPSC. We show that sncRNA PE yielded detectable editing rates in hiPSC ranging between 6.4% and 9.8%, which was further increased to 41% after a GFP-based fluorescence-activated cell sorting (FACS) cell sorting step. Furthermore, we show that selecting the high GFP expressing population improved editing efficiencies up to 3.2-fold compared to the low GFP expressing population, demonstrating that not only delivery but also the number of copies of the PE enzyme and/or pegRNA per cell are important for efficient editing. Edit rates were not improved when an additional silent protospacer-adjacent motif (PAM)-removing alteration was introduced in hiPSC at the target locus. Finally, there were no genome-wide off-target effects using pAIO-EF1α-PE2 and no off-target editing activity near the edit locus highlighting the accuracy of snc prime editors.

CONCLUSION

Taken together, our study shows an improved efficacy of EF-1α driven sncRNA pAIO-PE plasmids in hiPSC reaching high editing rates, especially after FACS sorting. Optimizing these sncRNA PE systems is of high value when considering future therapeutic in vivo use, where accuracy will be extremely important.

Characterization of the biochemical activity and tumor-promoting role of the dual protein methyltransferase METL-13/METTL13 in Caenorhabditis elegans

The methyltransferase-like protein 13 (METTL13) methylates the eukaryotic elongation factor 1 alpha (eEF1A) on two locations: the N-terminal amino group and lysine 55. The absence of this methylation leads to reduced protein synthesis and cell proliferation in human cancer cells. Previous studies showed that METTL13 is dispensable in non-transformed cells, making it potentially interesting for cancer therapy. However, METTL13 has not been examined yet in whole animals. Here, we used the nematode Caenorhabditis elegans as a simple model to assess the functions of METTL13. Using methyltransferase assays and mass spectrometry, we show that the C. elegans METTL13 (METL-13) methylates eEF1A (EEF-1A) in the same way as the human protein. Crucially, the cancer-promoting role of METL-13 is also conserved and depends on the methylation of EEF-1A, like in human cells. At the same time, METL-13 appears dispensable for animal growth, development, and stress responses. This makes C. elegans a convenient whole-animal model for studying METL13-dependent carcinogenesis without the complications of interfering with essential wild-type functions.

TOPK promotes the growth of esophageal cancer in vitro and in vivo by enhancing YB1/eEF1A1 signal pathway

T-LAK-originated protein kinase (TOPK), a dual specificity serine/threonine kinase, is up-regulated and related to poor prognosis in many types of cancers. Y-box binding protein 1 (YB1) is a DNA/RNA binding protein and serves important roles in multiple cellular processes. Here, we reported that TOPK and YB1 were both highly expressed in esophageal cancer (EC) and correlated with poor prognosis. TOPK knockout effectively suppressed EC cell proliferation and these effects were reversible by rescuing YB1 expression. Notably, TOPK phosphorylated YB1 at Thr 89 (T89) and Ser 209 (S209) amino acid residues, then the phosphorylated YB1 bound with the promoter of the eukaryotic translation elongation factor 1 alpha 1 (eEF1A1) to activate its transcription. Consequently, the AKT/mTOR signal pathway was activated by up-regulated eEF1A1 protein. Importantly, TOPK inhibitor HI-TOPK-032 suppressed the EC cell proliferation and tumor growth by TOPK/YB1/eEF1A1 signal pathway in vitro and in vivo. Taken together, our study reveals that TOPK and YB1 are essential for the growth of EC, and TOPK inhibitors may be applied to retard cell proliferation in EC. This study highlights the promising therapeutic potential of TOPK as a target for treatment of EC.

Epigenetic Control of Translation Checkpoint and Tumor Progression via RUVBL1-EEF1A1 Axis

Epigenetic dysregulation is reported in multiple cancers including Ewing sarcoma (EwS). However, the epigenetic networks underlying the maintenance of oncogenic signaling and therapeutic response remain unclear. Using a series of epigenetics- and complex-focused CRISPR screens, RUVBL1, the ATPase component of NuA4 histone acetyltransferase complex, is identified to be essential for EwS tumor progression. Suppression of RUVBL1 leads to attenuated tumor growth, loss of histone H4 acetylation, and ablated MYC signaling. Mechanistically, RUVBL1 controls MYC chromatin binding and modulates the MYC-driven EEF1A1 expression and thus protein synthesis. High-density CRISPR gene body scan pinpoints the critical MYC interacting residue in RUVBL1. Finally, this study reveals the synergism between RUVBL1 suppression and pharmacological inhibition of MYC in EwS xenografts and patient-derived samples. These results indicate that the dynamic interplay between chromatin remodelers, oncogenic transcription factors, and protein translation machinery can provide novel opportunities for combination cancer therapy.

Arabidopsis translation factor eEF1Bγ impacts plant development and is associated with heat-induced cytoplasmic foci

The important role of translational control for maintenance of proteostasis is well documented in plants, but the exact mechanisms that coordinate translation rates during plant development and stress response are not well understood. In Arabidopsis, the translation elongation complex eEF1B consists of three subunits: eEF1Bα, eEF1Bβ, and eEF1Bγ. While eEF1Bα and eEF1Bβ have a conserved GDP/GTP exchange function, the function of eEF1Bγ is still unknown. By generating Arabidopsis mutants with strongly reduced eEF1Bγ levels, we revealed its essential role during plant growth and development and analysed its impact on translation. To explore the function of the eEF1B subunits under high temperature stress, we analysed their dynamic localization as green fluorescent protein fusions under control and heat stress conditions. Each of these fusion proteins accumulated in heat-induced cytoplasmic foci and co-localized with the stress granule marker poly(A)-binding protein 8-mCherry. Protein-protein interaction studies and co-expression analyses indicated that eEF1Bβ physically interacted with both of the other subunits and promoted their recruitment to cytoplasmic foci. These data provide new insights into the mechanisms allowing for rapid adaptation of translation rates during heat stress response.

Population Genetic Structure of Phlebotomus sergenti (Diptera: Psychodidae) Collected in Four Regions of Morocco Based on the Analysis of Cyt b and EF-1α Genes

Phlebotomus (Ph.) sergenti is the main vector of Leishmania (L.) tropica (Trypanosomatida: Trypanosomatidae), the causative agent of anthroponotic cutaneous leishmaniasis in Morocco. This species has an extended geographical distribution, wider than that of the parasite. The main objective of our study was to analyze the genetic diversity of Ph. sergenti collected in four foci in Morocco: Taza, Foum Jemâa, El Hanchane, and Ouarzazate. We studied a set of diversity and population structure indices by sequencing two markers; nuclear EF-1α and mitochondrial Cyt b from 175 individual sand flies. Our results showed a considerable degree of intraspecific polymorphism with a high number of haplotypes identified in both genes. Many polymorphic sites detected in the Cyt b sequences (SCyt b = 45) indicate that it is the most polymorphic marker showing a distinct distribution of haplotypes according to their geographical origin, whereas the EF-1α marker showed no geographical isolation. Analysis by Tajima's D and Fu's Fs tests revealed a possible recent expansion of the populations, especially with the EF-1α marker, showing significant values in Taza and Ouarzazate sequences. The present study revealed significant genetic diversity within Ph. sergenti populations in Morocco. The results warrant further research using a combination of more than two markers including mitochondrial and non-mitochondrial markers, which may provide more information to clarify the genetic status of Ph. sergenti.

Analysis of eEF1A2 gene expression and copy number in cervical carcinoma

OBJECTIVE

To explore and analyze the expression of eukaryotic translation elongation factor 1 alpha 2 (eEF1A2) gene in cervical cancer tissues, its relationship with patient survival, gene mutations, and changes in copy number in cervical cancer and chronic cervicitis tissues.

METHODS

The expression of the eEF1A2 gene in cervical cancer and its relationship with patient survival were analyzed using gene expression profile interactive analysis. Changes in eEF1A2 expression in cervical cancer tissues were analyzed using cBioPortal, a portal for cancer genomics analysis. The eEF1A2 copy number in cervical cancer tissues and chronic cervicitis tissues was determined by real-time fluorescence quantitative polymerase chain reaction. The relationship between the expression of eEF1A2 protein and the clinical stage, pathological grade, and patient survival of cervical cancer was analyzed by the database: The Human Protein Atlas, an integrated repository portal for tumor-immune system interactions.

RESULTS

Gene expression profile interactive analysis database analysis showed no significant differences in the expression of eEF1A2 between cervical cancer and normal cervical tissues (P > .05). The eEF1A2 gene expression level was not correlated with the survival of cervical cancer patients (P > .05). Analysis of the cBioPortal database showed that 18 of 297 cervical cancer patients had eEF1A2 gene changes, including missense mutation, splice mutation, amplification, and messenger RNA increase. There was no significant difference in eEF1A2 gene copy number between cervical cancer and chronic cervicitis (P > .05). The Human Protein Atlas and an integrated repository portal for tumor-immune system interactions database analysis of immunohistochemical data showed that eEF1A2 protein expression was no significant difference in clinical stage, pathological grade and patient survival of cervical cancer (P > .05).

CONCLUSION

The eEF1A2 gene was mutated in cervical cancer tissues. The eEF1A2 gene copy number was not associated with changes in the expression of the eEF1A2 gene in cervical cancer tissues.

Diversity and Pathogenicity of Botryosphaeriaceae Associated with Macadamia Branch Dieback in Australia

Botryosphaeria branch dieback is a serious disease of macadamia in Australia, but its etiology has not been clearly defined, which limits effective disease control. Therefore, this study examined whether the causal agents of branch dieback in commercial macadamia orchards in five agroecological regions in Australia are similar in prevalence and aggressiveness. The identity of the causal agents was determined using conventional culturing techniques and DNA sequencing that targets the internal transcribed spacer (ITS), translation elongation factor 1-alpha (tef1α), β-tubulin (tub2), and DNA-directed RNA polymerase II second largest subunit (rpb2) gene loci. The pathogenic variation of the isolates, relative to the source (region and host plant part), was examined using in vivo and in planta assays. Lasiodiplodia and Neofusicoccum were the dominant fungal genera obtained from surveys of 59 macadamia orchards across the agroecological regions. Phylogenetic analysis of 52 representative isolates identified four putative novel Lasiodiplodia clades, with three other Lasiodiplodia spp. (Lasiodiplodia iraniensis, L. pseudotheobromae, and L. theobromae) and three Neofusicoccum spp. (Neofusicoccum luteum, N. mangroviorum, and N. parvum) from macadamia. L. pseudotheobromae that constituted 40% of the isolates from symptomatic tissues was the most prevalent in all the regions. Both the in vivo and in planta pathogenicity assays revealed that all isolates of the Botryosphaeriaceae, except N. mangroviorum, were pathogenic to macadamia. L. theobromae, N. luteum, and L. iraniensis were the most aggressive species causing dieback symptoms in macadamia.

Screening of genes encoding proteins that interact with ISG15: Probing a cDNA library from a snakehead fish cell line using a yeast two-hybrid system

Interferon-stimulated gene 15 (ISG15) regulates cellular life processes, including defense responses against infection by a variety of viral pathogens, by binding to target proteins. At present, various fish ISG15s have been identified, but the biological function of ISG15 in snakehead fish is still unclear. In this study, total RNA was extracted from snakehead fish cell line E11, ds cDNA was synthesized and purified using SMART technology, and the resulting cDNA library was screened by co-transforming yeast cells. The library titer was 4.28 × 10⁹ CFU/mL. Using snakehead ISG15 as the bait protein, the recombinant bait vector pGBKT7-ISG15 was constructed and transformed into the yeast strain Y2HGold. The toxicity and self-activation activity of the bait vector were detected on the deficient medium, and the prey proteins interacting with ISG15 were screened. In total, 19 interacting proteins of ISG15 were identified, including mitotic checkpoint protein BUB3, hypothetical protein SnRVgp6, elongation factor 1-beta, 60S ribosomal protein L9, dual specificity protein phosphatase 5-like, eukaryotic translation initiation factor 3 subunit I and ferritin. A yeast spotting assay further probed the interaction between ISG15 and DUSP5. These results increase our understanding of the interaction network of snakehead ISG15 and will aid in exploring the underlying mechanisms of snakehead ISG15 functions in the future.

High eEF1A1 Protein Levels Mark Aggressive Prostate Cancers and the In Vitro Targeting of eEF1A1 Reveals the eEF1A1-actin Complex as a New Potential Target for Therapy

Although the eukaryotic elongation factor eEF1A1 plays a role in various tumours, there is little information on its prognosis/therapeutic value in prostate carcinoma. In high-grade and castration-resistant prostate carcinoma (CRPC), the identification of novel therapeutic markers/targets remains a priority. The expression of eEF1A1 protein was determined in formalin-fixed, paraffin-embedded prostate cancer and hyperplasia tissue by IHC. The role of eEF1A1 was investigated in a cellular model using a DNA aptamer (GT75) we previously developed. We used the aggressive CRPC cancer PC-3 and non-tumourigenic PZHPV-7 lines. Cytotoxicity was measured by the MTS assay and eEF1A1 protein levels by in-cell Western assays. The mRNA levels of eEF1A1 were measured by qPCR and ddPCR. Higher expression of eEF1A1 was found in Gleason 7-8 compared with 4-6 tissues (Gleason ≥ 7, 87% versus Gleason ≤ 6, 54%; p = 0.033). Patients with a high expression of eEF1A1 had a worse clinical outcome. In PC-3, but not in PZHPV-7, GT75 decreased cell viability and increased autophagy and cell detachment. In PC-3 cells, but not in PZHPV-7, GT75 mainly co-localised with the fraction of eEF1A1 bound to actin. Overexpression of the eEF1A1 protein can identify aggressive forms of prostate cancer. The targeting of eEF1A1 by GT75 impaired cell viability in PC-3 cancer cells but not in PZHPV-7 non-tumourigenic cells, indicating a specific role for the protein in cancer survival. The eEF1A1-actin complexes appear to be critical for the viability of PC-3 cancer cells, suggesting that eEF1A1 may be an attractive target for therapeutic strategies in advanced forms of prostate cancer.

OUP accepted manuscript

Background

The glioblastoma-amplified sequence (GBAS) is a newly identified gene that is amplified in approximately 40% of glioblastomas. This article probes into the expression, prognostic significance, and possible pathways of GBAS in ovarian cancer (OC).

Method

Immunohistochemical methods were used to evaluate the expression level of GBAS in OC and its relationship with clinicopathological characteristics and prognosis. Glioblastoma-amplified sequence shRNA was designed to transfect into OC cell lines to silence GBAS expression, then detect the proliferation, apoptosis, and migration ability of the cell. Furthermore, an in vitro tumor formation experiment in mice was constructed to prove the effect of GBAS expression on the growth of OC in vivo. To further study the regulation mechanism of GBAS, we performed co-immunoprecipitation (Co-IP) and shotgun LC-MS mass spectrometry identification.

Results

Immunohistochemistry indicated that GBAS was markedly overexpressed in OC compared with normal ovarian tissue and was associated with lymph node metastasis. Inhibition of GBAS expression can significantly reduce OC cell proliferation, colony formation, promote cell apoptosis, and reduce the ability of cell migration and invasion. In vivo tumor formation experiments showed that the size and weight of tumors in mice after GBAS expression knockdown was significantly smaller. Glioblastoma-amplified sequence may be combined with elongation factor 1 alpha 1 (eEF1A1) to achieve its regulation in OC. Bioinformatics analysis data indicate that GBAS may be a key regulator of mitochondria-associated pathways, therefore controlling cancer progression. MicroRNA-27b, MicroRNA-23a, and MicroRNA-590 may directly targeting GBAS affects the biological behavior of OC cells.

Conclusion

The glioblastoma-amplified sequence may regulate the proliferation and metastasis of OC cells by combining with eEF1A1.

An Isoform of the Eukaryotic Translation Elongation Factor 1A (eEF1a) Acts as a Pro-Viral Factor Required for Tomato Spotted Wilt Virus Disease in Nicotiana benthamiana

The tripartite genome of the negative-stranded RNA virus Tomato spotted wilt orthotospovirus (TSWV) is assembled, together with two viral proteins, the nucleocapsid protein and the RNA-dependent RNA polymerase, into infectious ribonucleoprotein complexes (RNPs). These two viral proteins are, together, essential for viral replication and transcription, yet our knowledge on the host factors supporting these two processes remains limited. To fill this knowledge gap, the protein composition of viral RNPs collected from TSWV-infected Nicotiana benthamiana plants, and of those collected from a reconstituted TSWV replicon system in the yeast Saccharomyces cerevisiae, was analysed. RNPs obtained from infected plant material were enriched for plant proteins implicated in (i) sugar and phosphate transport and (ii) responses to cellular stress. In contrast, the yeast-derived viral RNPs primarily contained proteins implicated in RNA processing and ribosome biogenesis. The latter suggests that, in yeast, the translational machinery is recruited to these viral RNPs. To examine whether one of these cellular proteins is important for a TSWV infection, the corresponding N. benthamiana genes were targeted for virus-induced gene silencing, and these plants were subsequently challenged with TSWV. This approach revealed four host factors that are important for systemic spread of TSWV and disease symptom development.

A cleavage-based surrogate reporter for the evaluation of CRISPR-Cas9 cleavage efficiency

CRISPR-Cas9 is a powerful tool for genome engineering, but its efficiency largely depends on guide RNA (gRNA). There are multiple methods available to evaluate the efficiency of gRNAs, including the T7E1 assay, surveyor nuclease assay, deep sequencing, and surrogate reporter systems. In the present study, we developed a cleavage-based surrogate that we have named the LacI-reporter to evaluate gRNA cleavage efficiency. The LacI repressor, under the control of the EF-1α promoter, represses luciferase or EGFP reporter expression by binding to the lac operator. Upon CRISPR-Cas9 cleavage at a target site located between the EF-1α promoter and the lacI gene, repressor expression is disrupted, thereby triggering luciferase or EGFP expression. Using this system, we can quantitate gRNA cleavage efficiency by assessing luciferase activity or EGFP expression. We found a strong positive correlation between the cleavage efficiency of gRNAs measured using this reporter and mutation frequency, measured using surveyor and deep sequencing. The genome-editing efficiency of gRNAs was validated in human liver organoids. Our LacI-reporter system provides a useful tool to select efficient gRNAs for genome editing.

Select Porcine Elongation Factor 1α Sequences Mediate Stable High-Level and Upregulated Expression of Heterologous Genes in Porcine Cells in Response to Primate Serum

Genetically engineered (GE) pigs with various combinations of genetic profiles have been developed using heterologous promoters. This study aimed to identify autologous promoters for high and ubiquitous expression of xenotransplantation relevant genes in GE pigs. A 1.4 kb upstream regulatory sequence of porcine elongation factor 1α (pEF1α) gene was selected and isolated for use as a promoter. Activity of the pEF1α promoter was subsequently compared with that of the cytomegalovirus (CMV) promoter, CMV enhancer/chicken β-actin (CAG) promoter, and human EF1α (hEF1α) promoter in different types of pig-derived cells. Comparative analysis of luciferase and mutant human leukocyte antigen class E-F2A-β-2 microglobulin (HLA-E) expression driven by pEF1α, CMV, CAG, and hEF1α promoters revealed the pEF1α promoter mediated comparable expression levels with those of the CAG promoter in porcine ear skin fibroblasts (PEFs) and porcine kidney-15 (PK-15) cells, but lower than those of the CAG promoter in porcine aortic endothelial cells (PAECs). The pEF1α promoter provided long-term stable HLA-E expression in PEFs, but the CAG promoter failed to sustain those levels of expression. For xenogeneic serum-induced cytotoxicity assays, the cells were cultured for several hours in growth medium supplemented with primate serum. Notably, the pEF1α promoter induced significant increases in luciferase and HLA-E expression in response to primate serum in PAECs compared with those driven by the CAG promoter, suggesting the pEF1α promoter could regulate temporal expression of heterologous genes under xenogeneic-cytotoxic conditions. These results suggest the pEF1α promoter may be valuable for development of GE pigs spatiotemporally and stably expressing immunomodulatory genes for xenotransplantation.

On the Need to Tell Apart Fraternal Twins eEF1A1 and eEF1A2, and Their Respective Outfits

eEF1A1 and eEF1A2 are paralogous proteins whose presence in most normal eukaryotic cells is mutually exclusive and developmentally regulated. Often described in the scientific literature under the collective name eEF1A, which stands for eukaryotic elongation factor 1A, their best known activity (in a monomeric, GTP-bound conformation) is to bind aminoacyl-tRNAs and deliver them to the A-site of the 80S ribosome. However, both eEF1A1 and eEF1A2 are endowed with multitasking abilities (sometimes performed by homo- and heterodimers) and can be located in different subcellular compartments, from the plasma membrane to the nucleus. Given the high sequence identity of these two sister proteins and the large number of post-translational modifications they can undergo, we are often confronted with the dilemma of discerning which is the particular proteoform that is actually responsible for the ascribed biochemical or cellular effects. We argue in this review that acquiring this knowledge is essential to help clarify, in molecular and structural terms, the mechanistic involvement of these two ancestral and abundant G proteins in a variety of fundamental cellular processes other than translation elongation. Of particular importance for this special issue is the fact that several de novo heterozygous missense mutations in the human EEF1A2 gene are associated with a subset of rare but severe neurological syndromes and cardiomyopathies.

Evaluation of candidate reference genes for gene expression analysis in the brassica leaf beetle, Phaedon brassicae (Coleoptera: Chrysomelidae)

The brassica leaf beetle Phaedon brassicae is a notorious defoliator of cruciferous vegetables. However, few molecular studies of this pest have been conducted due to limited sequence data. Recently, RNA sequencing has offered a powerful platform to generate numerous transcriptomic data, which require RT-qPCR to validate target gene expression. The selection of reliable reference genes to normalize RT-qPCR data is a prerequisite for gene expression analysis. In the present study, the expression stabilities of eight candidate reference genes under biotic conditions (development stages and various tissues) and abiotic perturbations (thermal stress and pesticide exposure) were evaluated using four different statistical algorithms. The optimal suites of reference genes were recommended for the respective experimental conditions. For tissue expression analysis, RPL32 and EF-1α were recommended as the suitable reference genes. RPL19 and TBP were the optimal reference genes across different developmental stages. RPL32 and TBP were identified as the most suitable references for thermal stress. Furthermore, RPL32 and RPL19 were ranked as the best references for insecticide exposure. This work provides a systematic exploration of the optimal reference genes for the respective experimental conditions, and our findings would facilitate molecular studies of P. brassicae.

Elongation factor ELOF1 drives transcription-coupled repair and prevents genome instability

Correct transcription is crucial for life. However, DNA damage severely impedes elongating RNA polymerase II, causing transcription inhibition and transcription-replication conflicts. Cells are equipped with intricate mechanisms to counteract the severe consequence of these transcription-blocking lesions. However, the exact mechanism and factors involved remain largely unknown. Here, using a genome-wide CRISPR-Cas9 screen, we identified the elongation factor ELOF1 as an important factor in the transcription stress response following DNA damage. We show that ELOF1 has an evolutionarily conserved role in transcription-coupled nucleotide excision repair (TC-NER), where it promotes recruitment of the TC-NER factors UVSSA and TFIIH to efficiently repair transcription-blocking lesions and resume transcription. Additionally, ELOF1 modulates transcription to protect cells against transcription-mediated replication stress, thereby preserving genome stability. Thus, ELOF1 protects the transcription machinery from DNA damage via two distinct mechanisms.

High-level expression of the monomeric SARS-CoV-2 S protein RBD 320-537 in stably transfected CHO cells by the EEF1A1-based plasmid vector

The spike (S) protein is one of the three proteins forming the coronaviruses' viral envelope. The S protein of the Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) has a spatial structure similar to the S proteins of other mammalian coronaviruses, except for a unique receptor-binding domain (RBD), which is a significant inducer of host immune response. Recombinant SARS-CoV-2 RBD is widely used as a highly specific minimal antigen for serological tests. Correct exposure of antigenic determinants has a significant impact on the accuracy of such tests-the antigen has to be correctly folded, contain no potentially antigenic non-vertebrate glycans, and, preferably, should have a glycosylation pattern similar to the native S protein. Based on the previously developed p1.1 vector, containing the regulatory sequences of the Eukaryotic translation elongation factor 1 alpha gene (EEF1A1) from Chinese hamster, we created two expression constructs encoding SARS-CoV-2 RBD with C-terminal c-myc and polyhistidine tags. RBDv1 contained a native viral signal peptide, RBDv2 -human tPA signal peptide. We transfected a CHO DG44 cell line, selected stably transfected cells, and performed a few rounds of methotrexate-driven amplification of the genetic cassette in the genome. For the RBDv2 variant, a high-yield clonal producer cell line was obtained. We developed a simple purification scheme that consistently yielded up to 30 mg of RBD protein per liter of the simple shake flask cell culture. Purified proteins were analyzed by polyacrylamide gel electrophoresis in reducing and non-reducing conditions and gel filtration; for RBDv2 protein, the monomeric form content exceeded 90% for several series. Deglycosylation with PNGase F and mass spectrometry confirmed the presence of N-glycosylation. The antigen produced by the described technique is suitable for serological tests and subunit vaccine studies.

Transcriptional activities of human elongation factor-1α and cytomegalovirus promoter in transgenic dogs generated by somatic cell nuclear transfer

Recent advances in somatic cell nuclear transfer (SCNT) in canines facilitate the production of canine transgenic models. Owing to the importance of stable and strong promoter activity in transgenic animals, we tested human elongation factor 1α (hEF1α) and cytomegalovirus (CMV) promoter sequences in SCNT transgenic dogs. After transfection, transgenic donor fibroblasts with the hEF1α-enhanced green fluorescence protein (EGFP) transgene were successfully isolated using fluorescence-activated cell sorting (FACS). We obtained four puppies, after SCNT, and identified three puppies as being transgenic using PCR analysis. Unexpectedly, EGFP regulated by hEF1α promoter was not observed at the organismal and cellular levels in these transgenic dogs. EGFP expression was rescued by the inhibition of DNA methyltransferases, implying that the hEF1α promoter is silenced by DNA methylation. Next, donor cells with CMV-EGFP transgene were successfully established and SCNT was performed. Three puppies of six born puppies were confirmed to be transgenic. Unlike hEF1α-regulated EGFP, CMV-regulated EGFP was strongly detectable at both the organismal and cellular levels in all transgenic dogs, even after 19 months. In conclusion, our study suggests that the CMV promoter is more suitable, than the hEF1α promoter, for stable transgene expression in SCNT-derived transgenic canine model.

Effects of eEF1A2 knockdown on autophagy in an MPP+-induced cellular model of Parkinson's disease

1-Methyl-4-phenylpyridinium ion (MPP⁺) is widely used to induce a cellular model of Parkinson's disease (PD) in dopaminergic cell lines. Downregulation of the protein translation elongation factor 1 alpha (eEF1A) has been reported in the brain tissue of PD patients. eEF1A2, an isoform of eEF1A, is associated with lysosome biogenesis that involves the autophagy process. However, the role of eEF1A2 on autophagic activity in PD has not been elucidated. In this work, we investigated the role of eEF1A2 on autophagy using eEF1A2 siRNA knockdown in differentiated SH-SY5Y neuronal cells treated with MPP⁺. We found that eEF1A2 was upregulated in differentiated cells, which could be silenced by eEF1A2 siRNA. Significantly, cells treated with MPP⁺ after eEF1A2 knockdown showed a decreased number of LC3 puncta, decreased LC3-II/LC3-I ratio, and decreased phospho-Beclin-1, compared to the MPP⁺ alone group. These cells showed extensive areas of mitochondria damage, with a reduction of mitochondrial membrane potential, but reduced mitophagy as indicated by the reduced colocalization of LC3 puncta with damaged mitochondria. Cells with eEF1A2 siRNA plus MPP⁺ treatment aggravated α-synuclein accumulation but reduced colocalization with LC3. As a result, eEF1A2 knockdown decreased viability, increased apoptotic nuclei, increased caspase-3/7 activation and increased cleaved caspase-3 when cells were treated with MPP⁺. These results suggest that eEF1A2 is essential for dopaminergic neuron survival against MPP⁺, in part through autophagy regulation.

Transcriptome-based evaluation and validation of suitable housekeeping gene for quantification real-time PCR under specific experiment condition in teleost fishes

Quantification real-time PCR (qRT-PCR) is a common method in analysis of gene expression, but the stable reference genes for the normalization analysis have not been appreciated before identifying expression pattern of genes in teleost fishes. In this study, we selected eight candidate reference genes (18S, Actin, EF-1α, 40S, B2M, TUBA, UBCE and GAPDH) basing on transcriptome analysis and the traditional housekeeping genes, and analyzed the stability of the reference genes in spleen, head kidney and head kidney leukocytes (HKL) after pathogen challenge in Schizothorax prenanti (S. prenanti). Three common programs (geNorm, NormFinder and Bestkeeper) were used to evaluate the stability of the candidate reference genes. Two reference genes, Actin and EF-1α presented higher stability, while 18S and GAPDH were the lower stable genes, both in in vitro and in vivo. An important immune gene, toll-like receptor 22a (TLR22a), was selected to validate the stability of the proposed reference genes (Actin and EF-1α) across different experiment treatments. The results reveal that Actin and EF-1α are quite suitable reference genes for the normalization analysis. Otherwise, using the most stable gene Actin to validate the reliable of transcriptome data showed the high correlation between the fold change of transcriptome data and qRT-PCR data. In conclusion, our study not only acquired the suitable reference gene for the qRT-PCR assay under specific experiment condition, but also provided a comprehensive method to evaluate and validate the reference gene based on transcriptome analysis in teleost fishes.

Influence of heat stress on reference genes stability in heart and liver of two chickens genotypes

Introduction

Real-time polymerase chain reaction (RT-qPCR) is an important tool for analyzing gene expression. However, before analyzing the expression of target genes, it is crucial to normalize the reference genes, in order to find the most stable gene to be used as an endogenous control. A gene that remains stable in all samples under different treatments is considered a suitable normalizer. In this sense, we aimed to identify stable reference genes for normalization of target genes in the heart and liver tissues from two genetically divergent groups of chickens (Cobb 500^® commercial line and Peloco backyard chickens) under comfort and acute heat stress environmental conditions. Eight reference genes (ACTB, HPRT1, RPL5, EEF1, MRPS27, MRPS30, TFRC and LDHA) were analyzed for expression stability. The samples were obtained from 24 chickens, 12 from the backyard Peloco and 12 from the Cobb 500® line, exposed to two environmental conditions (comfort and heat stress). Comfort temperature was 23°C and heat stress temperature was 39.5°C for one hour. Subsequently, the animals were euthanized, and heart and liver tissue fragments were collected for RNA extraction and amplification. To determine the stability rate of gene expression, three different statistical algorithms were applied: BestKeeper, geNorm and NormFinder, and to obtain an aggregated stability list, the RankAgregg package of R software was used.

Results

The most stable genes using BestKeeper tool, including the two factors (genetic group and environmental condition), were LDHA, RPL5 and MRPS27 for heart tissue, and TFRC, RPL5 and EEF1 for liver tissue. Applying geNorm algorithm, the best reference genes were RPL5, EEF1 and MRPS30 for heart tissue and LDHA, EEF1 and RPL5 for liver. Using the NormFinder algorithm, the best normalizer genes were EEF1, RPL5 and LDHA in heart, and EEF1, RPL5 and ACTB in liver tissue. In the overall ranking obtained by RankAggreg package, considering the three algorithms, the RPL5, EEF1 and LDHA genes were the most stable for heart tissue, whereas RPL5, EEF1 and ACTB were the most stable for liver tissue.

Conclusion

According to the RankAggreg tool classification based on the three different algorithms (BestKeeper, geNorm and NormFinder), the most stable genes were RPL5, EEF1 and LDHA for heart tissue and RPL5, EEF1 and ACTB for liver tissue of chickens subjected to comfort and acute heat stress environmental conditions. However, the best reference genes may vary depending on the experimental conditions of each study, such as different breeds, environmental stressors, and tissues analyzed. Therefore, the need to perform priori studies to assay the best reference genes at the outset of each study is emphasized.

Molecular Characterization and Disease Control of Stem Canker on Royal Poinciana (Delonix regia) Caused by Neoscytalidium dimidiatum in the United Arab Emirates

In the United Arab Emirates (UAE), royal poinciana (Delonix regia) trees suffer from stem canker disease. Symptoms of stem canker can be characterized by branch and leaf dryness, bark lesions, discoloration of xylem tissues, longitudinal wood necrosis and extensive gumming. General dieback signs were also observed leading to complete defoliation of leaves and ultimately death of trees in advanced stages. The fungus, Neoscytalidium dimidiatum DSM 109897, was consistently recovered from diseased royal poinciana tissues; this was confirmed by the molecular, structural and morphological studies. Phylogenetic analyses of the translation elongation factor 1-a (TEF1-α) of N. dimidiatum from the UAE with reference specimens of Botryosphaeriaceae family validated the identity of the pathogen. To manage the disease, the chemical fungicides, Protifert®, Cidely® Top and Amistrar® Top, significantly inhibited mycelial growth and reduced conidial numbers of N. dimidiatum in laboratory and greenhouse experiments. The described "apple bioassay" is an innovative approach that can be useful when performing fungicide treatment studies. Under field conditions, Cidely® Top proved to be the most effective fungicide against N. dimidiatum among all tested treatments. Our data suggest that the causal agent of stem canker disease on royal poinciana in the UAE is N. dimidiatum.

Effects of eEF1A1 targeting by aptamer/siRNA in chronic lymphocytic leukaemia cells

BACKGROUND

The effectiveness of therapies for chronic lymphocytic leukemia (CLL), the most common leukemia in Western countries adults, can be improved via a deeper understanding of its molecular abnormalities. Whereas the isoforms of the eukaryotic elongation factor 1A (eEF1A1 and eEF1A2) are implicated in different tumors, no information are available in CLL.

METHODS

eEF1A1/eEF1A2 amounts were quantitated in the lymphocytes of 46 CLL patients vs normal control (real time PCR, western blotting). eEF1A1 role in CLL was investigated in a cellular (MEC-1) and animal model of CLL via its targeting by an aptamer (GT75) or a siRNA (siA1) delivered by electroporation (in vitro) or lipofection (in vivo).

RESULTS

eEF1A1/eEF1A2 were elevated in CLL lymphocytes vs control. eEF1A1 but not eEF1A2 levels were higher in patients which died during the study compared to those surviving. eEF1A1 targeting (GT75/siA1) resulted in MEC-1 viability reduction/autophagy stimulation and in vivo tumor growth down-regulation.

CONCLUSIONS

The increase of eEF1A1 in dead vs surviving patients may confer to eEF1A1 the role of a prognostic marker for CLL and possibly of a therapeutic target, given its involvement in MEC-1 survival. Specific aptamer/siRNA released by optimized delivery systems may allow the development of novel therapeutic options.

Prevalence and antifungal susceptibility of Sporothrix species in Jiangxi, central China

Sporotrichosis is a subcutaneous mycosis caused by traumatic inoculation of pathogenic Sporothrix species. Until recently, Sporothrix globosa was considered as the unique Chinese species causing this disorder. In the present study, 33 clinical Sporothrix strains isolated from Jiangxi, China, were classified and antifungal susceptibility for each strain was determined. Thirteen S. globosa strains and 20 S. schenckii strains were identified by morphology and by multilocus analysis using rDNA ITS, CAL, and EF1α (i.e., internal transcribed spacer, calmodulin and elongation factor-1α). In vitro antifungal susceptibility testing of yeast phases indicated that itraconazole, terbinafine, and posaconazole were most effective against both species, followed by amphotericin B and voriconazole, while fluconazole, 5-fluorocytosine had low efficacy with high MICs. Co-occurrence of S. schenckii and S. globosa in central China may indicate different routes of transmission in this area.

Efficient tissue-type specific expression of target genes in a tetracycline-controlled manner from the ubiquitously active Eef1a1 locus

Using an efficient gene targeting approach, we developed a novel mouse line that expresses the tetracycline-controlled transactivator (tTA) from the constitutively active Eef1a1 locus in a Cre recombinase-inducible manner. The temporally and spatially controlled expression of the EF1-LSL-tTA knockin and activation of tTA-driven responder transgenes was tested using four transgenic lines that express Cre under tissue-specific promoters of the pancreas, mammary gland and other secretory tissues, as well as an interferon-inducible promoter. In all models, the endogenous Eef1a1 promoter facilitated a cell-type-specific activation of target genes at high levels without exogenous enhancer elements. The applicability of the EF1-LSL-tTA strain for biological experiments was tested in two studies related to mammary gland development and tumorigenesis. First, we validated the crucial role of active STAT5 as a survival factor for functionally differentiated epithelial cells by expressing a hyperactive STAT5 mutant in the mammary gland during postlactational remodeling. In a second experiment, we assessed the ability of the EF1-tTA to initiate tumor formation through upregulation of mutant KRAS. The collective results show that the EF1-LSL-tTA knockin line is a versatile genetic tool that can be applied to constitutively express transgenes in specific cell types to examine their biological functions at defined developmental stages.

Conventional plasmid DNAs with a CpG-containing backbone achieve durable transgene expression in mouse liver

BACKGROUND

Durable transgene expression from plasmid DNAs is the key to gene therapy with non-viral vectors. A comparison of the durability of transgene expression from plasmid DNAs with the CpG-free and -containing backbones is important.

METHODS

We constructed plasmid DNAs with the CpG-containing backbone, various transcription regulatory sequences with and without CpG, and the gene encoding Gaussia princeps luciferase, which is apparently non-immunogenic. The tail vein hydrodynamics-based method was used for plasmid injection into mice, and the luciferase activity in serum was tracked for 28 days.

RESULTS

The plasmid DNAs containing the albumin promoter [with or without the cytomegalovirus (CMV) enhancer] and the elongation factor (EF)1α promoter plus the CMV enhancer exhibited long-term luciferase expression. The expression from the plasmid DNA containing the albumin promoter without the CMV enhancer was maintained for at least 24 weeks and was similar to that from the corresponding CpG-free plasmid DNA.

CONCLUSIONS

The results obtained in the present study suggest that special sequences/systems are unnecessary for durable transgene expression from plasmid DNAs when the proper transcription regulatory sequences are used.

Selection of valid reference genes for quantitative real-time PCR in Cotesia chilonis (Hymenoptera: Braconidae) exposed to different temperatures

In quantitative real-time PCR (qRT-PCR), data are normalized using reference genes, which helps to control for internal differences and reduce error among samples. In this study, the expression profiles of eight candidate housekeeping genes, 18S ribosomal (18S rRNA), elongation factor (EF1), glyceraldehyde-3-phosphate dehydrogenase (GAPDH), ribosomal protein L10 (RPL10), ribosomal protein L17 (RPL17), histone 3 (H3), arginine kinase (AK), amd β-Actin (ACTB), were evaluated in the parasitic wasp Cotesia chilonis in response to different temperatures. Specifically, the performance and stabilities of these genes were compared in adult wasps maintained in a growth condition at 27°C (normal storage conditions) and in adults obtained from pupae refrigerated at 4°C for five days (cold storage conditions). Data were analyzed using the ΔCt method, BestKeeper, NormFinder, and geNorm. The optimal numbers and stabilities of reference genes varied between the two temperature treatments (27°C and 4°C). In samples stored at normal developmental temperature (27°C), the requirement for normalization in response to low temperature exposures was three genes (18S, H3, AK), whereas normalization in response to high temperature exposures required only two reference genes (GAPDH, ACTB). In samples stored at cold temperature (4°C), for low temperature exposures two reference genes (RPL17, RPL10) were required for standardization, while following high temperature exposures three reference genes (18S, H3, ACTB) were needed. This study strengthens understanding of the selection of reference genes before qRT-PCR analysis in C. chilonis. The reference genes identified here will facilitate further investigations of the biological characteristics of this important parasitoid.

Phylogenetic re-evaluation of the Grosmannia penicillata complex (Ascomycota, Ophiostomatales), with the description of five new species from China and USA

The Grosmannia penicillata complex (Ophiostomatales, Ascomycota) is one of the major species complexes in Leptographium sensu lato. Most of these are wood staining fungi associated with conifer-infesting bark beetles, and the complex encompasses the type species of the genus Grosmannia. Yet the phylogenetic relationships of species within the complex is unresolved. The aim of this study was to re-evaluate the circumscriptions of all known species in the G. penicillata complex, as well as isolates resembling G. penicillata obtained from a recent survey in China. Phylogenetic analyses of four gene regions: Internal transcribed spacer 2 and large subunit (ITS2-LSU), beta-tubulin (TUB), calmodulin (CAL), and translation elongation factor 1 alpha (TEF-1α) resolved the relationships of 15 species, including four new species (Grosmannia xianmiense sp nov., Grosmannia purpurea sp. nov., Grosmannia crassifolia sp. nov. and Grosmannia maixiuense sp. nov.), from China. Some isolates from pine in the USA that had previously been identified as Grosmannia abietina, represented a distinct taxon that is described here as Grosmannia xeno-abietina sp. nov.

Selection of candidate reference genes for RT-qPCR analysis in Argulus siamensis and their validation through screening of drugs and drug targets

Argulus spp. are economically important fish ectoparasites. The development of antiparasitic drugs is thus important and real time PCR is an indispensable tool in drug development. The analytical potential of RT-PCR depends upon accurate normalisation by the use of stable reference genes. Here, we identified stable reference genes of Argulus siamensis for validation of efficacy of drugs and drug targets. Seven candidate genes were evaluated by evaluating their expression under different states of Argulus using the RefFinder tool. The four algorithms together generated a comprehensive ranking with elongation factor-1 alpha (EF-1α) being the most stable and 18S ribosomal protein (18S) the least stable gene. Taking EF-1α and 18S genes as references, the effectiveness of six anti-parasitic compounds against Argulus was evaluated by studying their effect on the expression pattern of few ion channel genes; this was to understand their mode of action, besides validating the reference genes. EF-1α was found to be the most stable gene in the validation. Collectively, this study is the first report to validate the optimal reference genes of A. siamensis for normalisation, and the potential of the ion channel genes for evaluating effective drug targets in parasite control.

Limitations of dual-fluorescent HIV reporter viruses in a model of pre-activation latency

INTRODUCTION

HIV latency can be established in vitro following direct infection of a resting CD4+ T cell (pre-activation latency) or infection of an activated CD4+ T cell which then returns to a resting state (post-activation latency). We modified a previously published dual-fluorescent reporter virus seeking to track the establishment and reactivation of pre-activation latency in primary CD4+ T cells.

METHODS

A previously published dual-fluorescent reporter virus was modified so that expression of enhanced green fluorescent protein (GFP) was under control of the elongation factor 1 alpha (EF1α) promoter to detect latent infection, and E2 crimson (E2CRM) was under control of the nef promoter to detect productive infection. NL4.3 that expressed GFP in place of nef was used as a positive control. We infected the Jurkat T-cell line and primary CD4+ T cells that were either unstimulated or stimulated with either the chemokine CCL19 or phytohaemagglutinin (PHA)/IL-2 and quantified the expression of both fluorescent proteins by flow cytometry. The study was carried out over a period of two years from September 2016 to October 2018.

RESULTS AND DISCUSSION

Expression of both fluorophores was detected following infection of the Jurkat T-cell line while only low levels of the latent reporter were observed following infection of primary CD4+ T cells. In unstimulated and CCL19-treated CD4+ T cells, expression of the GFP latent reporter, increased after further activation of the cells with PHA/phorbol 12-myristate 13-acetate (PMA).

CONCLUSIONS

Our findings demonstrate that the EF1α promoter has poor constitutive expression in resting CD4+ T cells. Therefore, dual-fluorescent reporter viruses with the EF1α promoter may underestimate the frequency of latent infection in resting CD4+ T cells.

Modulating transcription through development of semi-synthetic yeast core promoters

Altering gene expression regulation by promoter engineering is a very effective way to fine-tune heterologous pathways in eukaryotic hosts. Typically, pathway building approaches in yeast still use a limited set of long, native promoters. With the today’s introduction of longer and more complex pathways, an expansion of this synthetic biology toolbox is necessary. In this study we elucidated the core promoter structure of the well-characterized yeast TEF1 promoter and determined the minimal length needed for sufficient protein expression. Furthermore, this minimal core promoter sequence was used for the creation of a promoter library covering different expression strengths. This resulted in a group of short, 69 bp promoters with an 8.0-fold expression range. One exemplar had a two and four times higher expression compared to the native CYC1 and ADH1 promoter, respectively. Additionally, as it was described that the protein expression range could be broadened by upstream activating sequences (UASs), we integrated earlier described single and multiple short, synthetic UASs in front of the strongest yeast core promoter. This approach resulted to further variation in protein expression and an overall promoter library spanning a 20-fold activity range and covering a length from 69 bp to maximally 129 bp. Furthermore, the robustness of this library was assessed on three alternative carbon sources besides glucose. As such, the suitability of short yeast core promoters for metabolic engineering applications on different media, either in an individual context or combined with UAS elements, was demonstrated.

Four new Ophiostoma species associated with conifer- and hardwood-infesting bark and ambrosia beetles from the Czech Republic and Poland

Fungi under the order Ophiostomatales (Ascomycota) are known to associate with various species of bark beetles (Coleoptera: Curculionidae: Scolytinae). In addition this group of fungi contains many taxa that can impart blue-stain on sapwood and some are important tree pathogens. A recent survey that focussed on the diversity of the Ophiostomatales in the forest ecosystems of the Czech Republic and Poland uncovered four putative new species. Phylogenetic analyses of four gene regions (ITS1-5.8S-ITS2 region, ß-tubulin, calmodulin, and translation elongation factor 1-α) indicated that these four species are members of the genus Ophiostoma. All four newly described species can be distinguished from each other and from closely related species based on DNA sequence comparisons, morphological characters, growth rates, and their insect associations. Based on this study four new taxa can be circumscribed and the following names are provided: Ophiostoma pityokteinis sp. nov., Ophiostoma rufum sp. nov., Ophiostoma solheimii sp. nov., and Ophiostoma taphrorychi sp. nov. O. rufum sp. nov. is a member of the Ophiostoma piceae species complex, while O. pityokteinis sp. nov. resides in a discrete lineage within Ophiostoma s. stricto. O. taphrorychi sp. nov. together with O. distortum formed a well-supported clade in Ophiostoma s. stricto close to O. pityokteinis sp. nov. O. solheimii sp. nov. groups within a currently undefined lineage A, which also includes Ophiostoma grandicarpum and Ophiostoma microsporum. This study highlights the need for more intensive surveys that should include additional countries of Central Europe, insect vectors and host tree species in order to elucidate Ophiostoma species diversity in this region.

Expression of protein synthesis elongation factors in winter wheat and oat in response to heat stress

The aim of our work was to examine the expression and accumulation of EF-Tu and eEF1A in grain filing stage of five genotypes of winter wheat and one oat genotype in conditions of heat stress. In addition, the correlation between accumulation of elongation factors eEF1A and EF-Tu, and yield components of cereals in the field was investigated. Flag leaf protein samples were analyzed by immunoblotting. Flag leaves were collected under conditions of moderate (23 °C; MT) and high air temperature (38 °C; HT) in a field experiment. After the harvest, grain yield was determined. The yield components, the weight of dry seed and grains number per spike, were assessed in the stage of full physiological maturity of investigated cultivars. Obtained results revealed a difference in the level of EF-Tu accumulation both under conditions of moderate air temperatures and conditions of heat stress among investigated cultivars. Cultivar Zvezdana was the only one that showed increase in EF-Tu accumulation under HT (25%) compared to MT. Immunoblot analysis indicated that the highest increase of eEF1A accumulation (43%) in relation to moderate temperature was detected in cultivar Talas. A significant, positive, linear correlation was found between the expression of eEF1A and small grains productivity under heat-stress conditions.