Cytoplasmic Polyadenylation Element Binding Research Articles

Micro-RNAs, their target proteins, predispositions and the memory of filial imprinting

Visual imprinting is a learning process whereby young animals come to prefer a visual stimulus after exposure to it (training). The intermediate medial mesopallium (IMM) in the domestic chick forebrain is critical for visual imprinting and contributes to molecular regulation of memory formation. We investigated the role of micro-RNAs (miRNAs) in such regulation. Twenty-four hours after training, miRNA spectra in the left IMM were compared between chicks with high preference scores (strong memory for imprinting stimulus), and chicks with low preference scores (weak memory for imprinting stimulus). Using criteria of significance and expression level, we chose gga-miR-130b-3p for further study and found that down-regulation correlated with learning strength. No effect was detected in posterior nidopallium, a region not involved in imprinting. We studied two targets of gga-miR-130b-3p, cytoplasmic polyadenylation element binding proteins 1 (CPEB-1) and 3 (CPEB-3), in two subcellular fractions (P2 membrane-mitochondrial and cytoplasmic) of IMM and posterior nidopallium. Only in the left IMM was a learning-related effect observed, in membrane CPEB-3. Variances from the regression with preference score and untrained chicks suggest that, in the IMM, gga-miR-130b-3p level reflects a predisposition, i.e. capacity to learn, whereas P2 membrane-mitochondrial CPEB-3 is up-regulated in a learning-specific way.

A combinatorial code for mRNA 3'-UTR-mediated translational control in the mouse oocyte.

Meiotic maturation of mammalian oocytes depends on the temporally and spatially regulated cytoplasmic polyadenylation and translational activation of maternal mRNAs. Cytoplasmic polyadenylation is controlled by cis-elements in the 3′-UTRs of mRNAs including the polyadenylation signal (PAS), which is bound by the cleavage and polyadenylation specificity factor (CPSF) and the cytoplasmic polyadenylation element (CPE), which recruits CPE binding proteins. Using the 3′-UTRs of mouse Cpeb1, Btg4 and Cnot6l mRNAs, we deciphered the combinatorial code that controls developmental stage-specific translation during meiotic maturation: (i) translation of a maternal transcript at the germinal vesicle (GV) stage requires one or more PASs that locate far away from CPEs; (ii) PASs distal and proximal to the 3′-end of the transcripts are equally effective in mediating translation at the GV stage, as long as they are not close to the CPEs; (iii) Both translational repression at the GV stage and activation after germinal vesicle breakdown require at least one CPE adjacent to the PAS; (iv) The numbers and positions of CPEs in relation to PASs within the 3′-UTR of a given transcript determines its repression efficiency in GV oocytes. This study reveals a previously unrecognized non-canonical mechanism by which the proximal PASs mediate 3′-terminal polyadenylation and translation of maternal transcripts.

CPEB2 Is Necessary for Proper Porcine Meiotic Maturation and Embryonic Development.

Oocyte meiotic maturation and embryogenesis are some of the most important physiological processes that occur in organisms, playing crucial roles in the preservation of life in all species. The post-transcriptional regulation of maternal messenger ribonucleic acids (mRNAs) and the post-translational regulation of proteins are critical in the control of oocyte maturation and early embryogenesis. Translational control affects the basic mechanism of protein synthesis, thus, knowledge of the key components included in this machinery is required in order to understand its regulation. Cytoplasmic polyadenylation element binding proteins (CPEBs) bind to the 3′-end of mRNAs to regulate their localization and translation and are necessary for proper development. In this study we examined the expression pattern of cytoplasmic polyadenylation element binding protein 2 (CPEB2) both on the mRNA (by real-time quantitative reverse transcription polymerase chain reaction, qRT-PCR) and protein (by Western blotting, WB) level, as well as its localization during the meiotic maturation of porcine oocytes and early embryonic development by immunocytochemistry (ICC). For the elucidation of its functions, CPEB2 knockdown by double-strand RNA (dsRNA) was used. We discovered that CPEB2 is expressed during all stages of porcine meiotic maturation and embryonic development. Moreover, we found that it is necessary to enable a high percentage of oocytes to reach the metaphase II (MII) stage, as well as for the production of good-quality parthenogenetic blastocysts.

Corrigendum to: Cytoplasmic polyadenylation element binding protein 2 (CPEB2) is required for tight-junction assembly for establishment of porcine trophectoderm epithelium.

Cytoplasmic polyadenylation element binding protein (CPEB) is an RNA-binding protein that promotes elongation of poly(A) tails and regulates mRNA translation. CPEB depletion in mammary epithelium is known to disrupt tight-junction (TJ) assembly via mislocalisation of tight junction protein 1 (TJP1), but the role of CPEB in the biological functions associated with TJs has not yet been studied. The objective of this study was to investigate the roles of CPEB2 during porcine parthenote development. CPEB2 was detected in both the nuclei and apical cytoplasm at the 4- and 8-cell stages and was localised to cell-cell contact after the initiation of the morula stage. Its depletion led to retarded blastocyst formation caused by impaired TJ assembly. Moreover, transcription of TJ-associated genes, including TJP1, Coxsackie virus and adenovirus receptor (CXADR) and occludin (OCLN), was not affected, but the corresponding proteins were not properly localised at the apical cell membrane in morulae, suggesting that CPEB2 confers mRNA stability or determines subcellular localisation for translation. Remarkably reduced relative levels of TJP1 transcripts bearing the 3'-untranslated region were noted, indicating that CPEB2 mediates TJP1 mRNA stability. In conclusion, our findings demonstrate that because of its regulation of TJP1, CPEB2 is required for TJ assembly during porcine blastocyst development.

Autism-like phenotype and risk gene mRNA deadenylation by CPEB4 mis-splicing.

Common genetic contributions to autism spectrum disorder (ASD) reside in risk-gene variants that individually have minimal effect-sizes. Since neurodevelopment-perturbing environmental factors also underlie idiopathic-ASD, it is crucial to identify altered regulators able to orchestrate multiple ASD-risk genes during neurodevelopment. Cytoplasmic polyadenylation element binding proteins 1-4 (CPEB1-4) regulate translation of specific mRNAs by modulating their poly(A)-tail and participate in embryonic development and synaptic plasticity. Here we find that CPEB4 binds transcripts of most high-confidence ASD genes. Idiopathic-ASD brains show CPEB4 transcript isoform imbalance due to decreased inclusion of a neuronal-specific microexon together with a new molecular signature of global poly(A)-tail shortening that remarkably impacts high-confidence ASD-risk genes with concomitant reduction of their protein levels. Equivalent CPEB4 transcript isoform imbalance in mice mimics the mRNA-polyadenylation and protein level changes of ASD genes and induces ASD-like neuroanatomical, electrophysiological and behavioral phenotypes. Altogether, these data unravel CPEB4 as a novel regulator of ASD-risk genes.

The research progress of CPEB4 in tumor

Cytoplasmic polyadenylation element binding protein 4 (Cytoplasmic polyadenylation element binding protein 4, CPEB4) ,a newly discovered member of the cytoplasmic polyadenylation element binding proteins, is a kind of RNA binding proteins with mediator of mRNA cytoplasmic polyadenylation and translation. CPEB4 plays an important role in the proliferation, migration, invasion and interstitial transformation of many tumors. In recent years, studies have shown that CPEB4 has abnormal expression in a variety of human tumors, and the abnormal expression of cancer patients has a significant correlation with the prognosis. Based on the current research progress, the purpose of this article is to further understand the relationship between CPEB4 and malignant tumor and its molecular mechanism of regulating tumorigenesis and to provide a new direction and means for the molecular diagnosis and targeted therapy of malignant tumor.

PO-305 Depletion of CPEB4 in the metastatic niche enhances metastatic growth

IntroductionMetastasis is the primary cause of death in cancer patients. The implantation and growth of metastatic cells in secondary organs is dependent on both cell-intrinsic factors and microenvironmental (‘host’) factors. Host cells are activated in response to oncogenic signals to acquire pro- or anti-tumoral properties, but the mechanisms of translational control that regulate this process remain largely unknown. Here, we study the role of the RNA-binding protein Cytoplasmic Polyadenylation Element Binding Protein 4 (CPEB4) in the metastatic niche. CPEB4 regulates temporally and spatially the translation efficiency and stability of up to 30% of mammalian mRNAs, and has been shown to regulate the expression of inflammation and angiogenesis-related genes such as VEGFA and IL6 in non-tumoral contexts.Material and methodsThe metastatic melanoma cell line B16F10 was used in an experimental metastasis assay to determine the contribution of host CPEB4 to metastatic growth. Syngenic wild type (WT) and CPEB4 full knock-out (KO) animals were tail-vein injected with B16F10 and lung metastasis number and size were quantified. Immune cell infiltration in untreated or tumor-bearing WT and KO was measured by FACS and IHC.Results and discussionsDepletion of host CPEB4 resulted in an increased lung metastasis size and a higher frequency of extrapulmonary metastasis. In contrast, primary tumour growth was comparable between WT and KO animals, suggesting that stromal CPEB4 has a prevailing role in secondary organs compared to B16F10 primary tumour niche. In addition, immunophenotyping analysis of metastatic organs revealed alterations in the immune cell composition of CPEB4 KO lungs.ConclusionOur preliminary results suggest that host CPEB4 is required to restrain metastatic growth. We hypothesised that lacking CPEB4 favours a more pro-metastatic environment due to changes in the immune cell compartment of the metastatic niche. Our future experiments will address whether CPEB4 depletion impairs directly immune cell function in a cell autonomous manner or whether other lung microenvironment cell types mediate the observed alterations.

MicroRNA-183 induces epithelial-mesenchymal transition and promotes endometrial cancer cell migration and invasion in by targeting CPEB1.

The aim of this study is to evaluate the ability of microRNA-183 (miR-183) to influence epithelial-mesenchymal transition (EMT) and cell proliferation, migration, invasion, and apoptosis in endometrial cancer (EC) by targeting cytoplasmic polyadenylation element binding protein 1(CPEB1). EC tissues with matched nonmalignant tissues were collected from 208 EC patients. Ishikawa and RL95-2 cells were selected for cell experiments in vitro and each kind of cells were grouped into blank, negative control (NC), miR-183 mimic, miR-183 inhibitor, CPEB1 overexpression, and miR-183 mimic + CPEB1 overexpression groups. Expressions of miR-183, CPEB1, E-cadherin, and Vimentin were determined by reverse transcription quantitative polymerase chain reaction (RT-qPCR) and Western blotting. Cell viability, colony formation ability, migration, invasion, and apoptosis were assessed by MTT assay, clone formation assay, scratch test, Transwell assay, and flow cytometry. In vivo tumorigenesis of Ishikawa cells was evaluated by tumor formation in nude mice. The miR-183 expression was higher, but the CPEB1 expression was lower in EC tissues than in adjacent nonmalignant tissues. CPEB1 was confirmed as the target of miR-183 by dual-luciferase reporter assay. The miR-183 mimic group had increased cell viability, colony formation ability, cell invasion and migration, tumor volume and weight in nude mice, but decreased cell apoptosis when compared with the blank group. The expression of E-cadherin was down-regulate, but expression of Vimentin was up-regulate in the miR-183 mimic group in comparison with the blank group. In terms of a comparison between the blank group and CPEB1 overexpression group, the CPEB1 overexpression group had suppressed cell viability, colony formation ability, cell invasion and migration, tumor volume and weight, but increased cell apoptosis. The expression of E-cadherin was up-regulated, but the expression of Vimentin was down-regulated in the CPEB1 overexpression group in comparison with the blank group. The miR-183 mimic + CPEB1 overexpression group had higher miR-183 expression than the blank group. These findings indicate that miR-183 induces EMT, inhibits apoptosis, and promotes cell proliferation, migration, invasion, and in vivo tumorigenesis in EC by targeting CPEB1.

Role of Cyclin A2 In Aging Hippocampus And rRna Dynamics

BackgroundNovel functions of cyclin A2 (CCNA2) have been demonstrated including DNA synthesis initiation and progression, DNA repair, and protein translation through RNA binding. Previously, we reported that loss of CCNA2 leads to hippocampal defects characterized by abnormal DNA repair and impaired performance on behavioral tests due to memory and learning deficits. Abnormalities in RNA processing and synaptic plasticity are mechanisms associated with deficits in memory and aging. This study was addressed to investigate effects of cyclin A2 loss on modulation of RNA processing in the hippocampus of aged mice.MethodsAll work involving animals was performed under the auspices of a protocol approved by the Ohio State University Institutional Animal Care and Use Committee. CamkIIα‐cre mice were interbred with CCNA2fl/fl mice to achieve adult ablation of CCNA2 in the hippocampus and cerebral cortex. To evaluate brain morphology, animals were sacrificed at 8 months. After fixed in 4% paraformaldehyde, crysections were obtained at 12 μm. Electron microscopy was performed and number of synapses and polyribosomes were quantified.ResultsUltrastructural analysis of Stratum Moleculare (SM) and Reticulare (SR) in 8mo mices showed a decrease of the synapse density in CamkIIαcre CCNA2 fl/fl mices as compared with control. However, quantity of ribosomes was increased only in SM of the hippocampus in mutant mices. Immunostaining for ribosomal RNA (rRNA) revealed an accumulation of rRNA granules in dentate gyrus and Cornu Ammonis (CA) both regions of the hippocampus. Quantitative analysis resulted an increased rRNA in the SR. To elucidate if mechanisms of translational regulation are modified by the lack of CCNA2 we screened for alterations of 40S ribosomal protein S6 (S6), and translational repressor eukaryotic initiation factor 4E binding protein (ELF4E) and cytoplasmic polyadenylation element binding protein 1 (CPEB1).ConclusionsOur data shows a distinct role for CCNA2 in adult hippocampus in the regulation of synaptic density as well as the prevention of rRNA granule formation. Alterations in RNA dynamics caused by loss of CCNA2 may be implicated in neuronal disorders and neurodegeneration.Support or Funding InformationThis work was sponsored by NIH/NHLBI grants RO1 HL132354This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Importance of ERK1/2 in Regulation of Protein Translation during Oocyte Meiosis.

Although the involvement of the extracellular signal-regulated kinases 1 and 2 (ERK1/2) pathway in the regulation of cytostatic factor (CSF) activity; as well as in microtubules organization during meiotic maturation of oocytes; has already been described in detail; rather less attention has been paid to the role of ERK1/2 in the regulation of mRNA translation. However; important data on the role of ERK1/2 in translation during oocyte meiosis have been documented. This review focuses on recent findings regarding the regulation of translation and the role of ERK1/2 in this process in the meiotic cycle of mammalian oocytes. The specific role of ERK1/2 in the regulation of mammalian target of rapamycin (mTOR); eukaryotic translation initiation factor 4E (eIF4E) and cytoplasmic polyadenylation element binding protein 1 (CPEB1) activity is addressed along with additional focus on the other key players involved in protein translation.

Knockdown of CPEB4 expression suppresses cell migration and invasion via Akt pathway in non-small cell lung cancer.

Cytoplasmic polyadenylation element binding protein 4 (CPEB4) could be an important regulator in variety of cancers. However, the biological function and the underlying molecular mechanism of CPEB4 in non-small cell lung cancer (NSCLC) remains unknown. In this study, we investigated the metastasis role of CPEB4 in NSCLC cells, we knocked down CPEB4 using siRNA. Transwell migration assay and cell invasion assay on Matrigel were presented, and cell migration was also determined by scratch-healing assay. ROS generation were determined by fluorescence probe DCFH2-DA. The protein expression was assessed by ELISA and Western blot analysis. LY294002 were used to inhibit PI3 K/Akt signaling. The data showed that knockdown of CPEB4 inhibited the migration and invasion of NSCLC. Moreover, silencing of CPEB4 reduced Snail and MMP-3 expression in vitro. We also indicated that CPEB4 knockdown increased the ROS expression. Furthermore, we found that silencing of CPEB4 decreased pAkt expression. Taken all together, our data demonstrated that silencing of CPEB4 induces ROS generation, thus suppressing the Akt expression, which finally prevents NSCLC cells invasion and migration. Therefore, CPEB4 may regard as a target to inhibit NSCLC invasion and metastasis through Akt pathway.

Regulation of Adult CNS Axonal Regeneration by the Post-transcriptional Regulator Cpeb1.

Adult mammalian central nervous system (CNS) neurons are unable to regenerate following axonal injury, leading to permanent functional impairments. Yet, the reasons underlying this regeneration failure are not fully understood. Here, we studied the transcriptome and translatome shortly after spinal cord injury. Profiling of the total and ribosome-bound RNA in injured and naïve spinal cords identified a substantial post-transcriptional regulation of gene expression. In particular, transcripts associated with nervous system development were down-regulated in the total RNA fraction while remaining stably loaded onto ribosomes. Interestingly, motif association analysis of post-transcriptionally regulated transcripts identified the cytoplasmic polyadenylation element (CPE) as enriched in a subset of these transcripts that was more resistant to injury-induced reduction at the transcriptome level. Modulation of these transcripts by overexpression of the CPE binding protein, Cpeb1, in mouse and Drosophila CNS neurons promoted axonal regeneration following injury. Our study uncovered a global evolutionarily conserved post-transcriptional mechanism enhancing regeneration of injured CNS axons.

Effects of Lidocaine-Mediated CPEB3 Upregulation in Human Hepatocellular Carcinoma Cell Proliferation In Vitro.

Lidocaine displays antitumor activity by inducing apoptosis and suppressing tumor growth in human hepatocellular carcinoma (HepG2) cells in vitro. However, the molecular mechanism underlying lidocaine-mediated antitumor activity is unclear. In this study, HepG2 cells were treated with lidocaine, and cell proliferation and colony-forming ability were assessed. The expression level of cytoplasmic polyadenylation element binding protein 3 (CPEB3) was detected by real-time quantitative PCR and western blot. Lidocaine treatment resulted in decreased HepG2 cell viability and colony formation in a dose-dependent manner. In hepatocellular carcinoma patient samples, CPEB3 was downregulated and was associated with poor prognosis and high-grade malignancy. Additionally, CPEB3 was a critical mediator of lidocaine-induced repression of HepG2 cell proliferation. These results demonstrated that lidocaine decreased cell viability and colony-forming ability of HepG2 cells by upregulating CPEB3 expression.

Anxiolytic effect of CPEB1 knockdown on the amygdala of a mouse model of inflammatory pain

Anxiety disorders are a category of mental disorders characterized by feelings of anxiety, stress, and fear attached to various sources. However, their pathogenesis is complicated and has not been fully elucidated. The amygdala is a vital brain region that regulates anxiety and mental disorders. Cytoplasmic polyadenylation element binding protein 1 (CPEB1) mediates the extension of the mRNA polyadenylation tail and facilitates the translation of target RNA. CPEB1 is closely related to neuronal diseases, such as Fragile X Syndrome, learning and memory disorders, and chronic pain. In this study, the role of CPEB1 in anxiety development was determined in a pain-mediated anxiety mouse model. The anxiety model was established in mice by injecting with Complete Freund’s Adjuvant (CFA) into the hindpaw. CFA injection then led to anxiety-like behaviors and increased the CPEB1 levels in the mouse basolateral amygdala (BLA). CPEB1 enhancement facilitated the translation of GluA1, GluN2A, GluN2B, PSD95, and GABA receptors, which disturbed the E/I balance in the BLA as shown by enhanced excitatory presynaptic release and reduced inhibitory presynaptic release. CPEB1 knockdown with AAV-CPEB1-shRNA alleviated the anxiety-like behaviors but not the pain-like behaviors by enhancing inhibitory transmission in the BLA of model mice. The data suggest that CPEB1 participates in anxiety development by regulating excitatory/inhibitory synaptic transmission in the BLA.

Mir-452-3p: A Potential Tumor Promoter That Targets the CPEB3/EGFR Axis in Human Hepatocellular Carcinoma.

Purpose:We proposed to investigate the effects of miR-452-3p on the proliferation and mobility of hepatocellular carcinoma (HCC) cells by targeting cytoplasmic polyadenylation element binding protein 3/estimated glomerular filtration rate (CPEB3/EGFR) axis.Methods:Quantitative real-time polymerase chain reaction (qRT-PCR) was used to detect miR-452-3p expression in 84 pairs of HCC tissues and adjacent tissues. Luciferase reporter assay was employed to examine the relationship between miR-452-3p and CPEB3. Microculture tetrazolium (MTT) assay, colony formation assay, flow cytometry detection, wound healing assay, and transwell assay were used to detect cell proliferation, cycle arrest, apoptosis, and mobility, respectively, in HCC, HepG2, and Huh-7. Western blot was used to detect protein expression levels in EGFR signaling pathway. Kaplan-Meier survival analysis was conducted to analyze the correlation between the miR-452-3p and CPEB3 expression levels and the survival of patients with HCC.Results:MiRNA-452-3p was found significantly upregulated in 84 human HCC sample tissues and cells in comparison with adjacent tissues and normal liver epithelial cells (P < .01). Luciferase reporter assay demonstrated that CPEB3 was a direct target of miR-452-3p. Overexpression of miR-452-3p promoted cell proliferation and mobility and suppressed apoptosis. MiR-452-3p enhanced EGFR and phosphorylated AKT (pAKT) expression but inhibited p21 expression level.Conclusion:MiR-452-3p promoted HCC cell proliferation and mobility by directly targeting the CPEB3/EGFR axis.

CPEB2 Activates GRASP1 mRNA Translation and Promotes AMPA Receptor Surface Expression, Long-Term Potentiation, and Memory

Activity-dependent synthesis of plasticity-related proteins is necessary to sustain long-lasting synaptic modifications and consolidate memory. We investigated the role of the translational regulator cytoplasmic polyadenylation element binding protein 2 (CPEB2) in learning and memory because regulated mRNA translation contributes to synaptic plasticity. Forebrain-restricted CPEB2 conditional knockout (cKO) mice exhibited impaired hippocampus-dependent memory in contextual fear conditioning and Morris water maze tests. CPEB2 cKO hippocampi showed impaired long-term potentiation in the Schaffer collateral-CA1 pathway. Reduced surface, but not total, expression of AMPA receptors (AMPARs) in CPEB2 KO neurons led us to identify that CPEB2 enhanced the translation of GRASP1 mRNA to facilitate recycling and maintain the surface level of AMPARs. Ectopic expression of CPEB2 or GRASP1 in CA1 areas of CPEB2 cKO mouse hippocampi rescued long-term potentiation and spatial memory in a water maze test. Thus, CPEB2-regulated GRASP1 mRNA translation is pivotal for AMPAR recycling, long-term plasticity, and memory.

Identification of miRNA and genes involving in osteosarcoma by comprehensive analysis of microRNA and copy number variation data.

The aim of the present study was to understand the molecular mechanisms of osteosarcoma by comprehensive analysis of microRNA (miRNA/miR) and copy number variation (CNV) microarray data. Microarray data (GSE65071 and GSE33153) were downloaded from the Gene Expression Omnibus. In GSE65071, differentially expressed miRNAs between the osteosarcoma and control groups were calculated by the Limma package. Target genes of differentially expressed miRNAs were identified by the starBase database. For GSE33153, PennCNV software was used to perform the copy number variation (CNV) analysis. Overlapping of the genes in CNV regions and the target genes of differentially expressed miRNAs were used to construct miRNA-gene regulatory network using the starBase database. A total of 149 differentially expressed miRNAs, including 13 downregulated and 136 upregulated, were identified. In the GSE33153 dataset, 987 CNV regions involving in 3,635 genes were identified. In total, 761 overlapping genes in 987 CNV regions and in the genes in 7,313 miRNA-gene pairs were obtained. miRNAs (hsa-miR-27a-3p, hsa-miR-124-3p, hsa-miR-9-5p, hsa-miR-182-5p, hsa-miR-26a-5p) and the genes [Fibroblast growth factor receptor substrate 2 (FRS2), coronin 1C (CORO1C), forkhead box P1 (FOXP1), cytoplasmic polyadenylation element binding protein 4 (CPEB4) and glucocorticoid induced 1 (GLCCI1)] with the highest degrees of association with osteosarcoma development were identified. Hsa-miR-27a-3p, hsa-miR-9-5p, hsa-miR-182-5p, FRS2, CORO1C, FOXP1 and CPEB4 may be involved in osteosarcoma pathogenesis, and development.

Metal Binding Properties of the N-Terminus of the Functional Amyloid Orb2.

The cytoplasmic polyadenylation element binding protein (CPEB) homologue Orb2 is a functional amyloid that plays a key regulatory role for long-term memory in Drosophila. Orb2 has a glutamine, histidine-rich (Q/H-rich) domain that resembles the Q/H-rich, metal binding domain of the Hpn-like protein (Hpnl) found in Helicobacter pylori. In the present study, we used chromatography and isothermal titration calorimetry (ITC) to show that the Q/H-rich domain of Orb2 binds Ni2+ and other transition metals ions with μM affinity. Using site directed mutagenesis, we show that several histidine residues are important for binding. In particular, the H61Y mutation, which was previously shown to affect the aggregation of Orb2 in cell culture, completely inhibited metal binding of Orb2. Finally, we used thioflavin T fluorescence and electron microscopy images to show that Ni2+ binding induces the aggregating of Orb2 into structures that are distinct from the amyloid fibrils formed in the absence of Ni2+. These data suggest that transition metal binding might be important for the function of Orb2 and potentially long-term memory in Drosophila.

Differential regulation of germ line apoptosis and germ cell differentiation by CPEB family members in C. elegans.

Cytoplasmic polyadenylation element binding (CPEB) proteins are evolutionary conserved RNA-binding proteins that control mRNA polyadenylation and translation. Orthologs in humans and other vertebrates are mainly involved in oogenesis. This is also the case for the C. elegans CPEB family member CPB-3, whereas two further CPEB proteins (CPB-1 and FOG-1) are involved in spermatogenesis. Here we describe the characterisation of a new missense allele of cpb-3 and show that loss of cpb-3 function leads to an increase in physiological germ cell death. To better understand the interaction and effect of C. elegans CPEB proteins on processes such as physiological apoptosis, germ cell differentiation, and regulation of gene expression, we characterised changes in the transcriptome and proteome of C. elegans CPEB mutants. Our results show that, despite their sequence similarities CPEB family members tend to have distinct overall effects on gene expression (both at the transcript and protein levels). This observation is consistent with the distinct phenotypes observed in the various CPEB family mutants.

Retraction Note: The microRNA-1246 promotes metastasis in non-small cell lung cancer by targeting cytoplasmic polyadenylation element-binding protein

The microRNAs present a class of non-coding RNAs which are usually implicated in tumor biology. Recent report has unraveled that a novel member of microRNA family called miR-1246. However, the functional role and molecular mechanisms of miR-1246 in non-small cell lung cancer (NSCLC) is still elusive. Using RT-PCR, luciferase reporter, mRNA microarrays, invasion and migration assays, we investigated the potential role of miR-1246 in the pathogenesis of NSCLC. In this study, we showed that miR-1246 markedly promoted NSCLC cell migration and invasion. Meanwhile, we found that cytoplasmic polyadenylation element binding protein 4 (CPEB4) might be involved and serve as a direct target of miR-1246 in NSCLC. CPEB4 knockdown substantially enhanced NSCLC migration and invasion resembling the effect of miR-1246 in NSCLC. CPEB4 is also frequently downregulated in NSCLC and decreased CPEB4 expression correlated with poor survival. These results suggested that the miR-1246 may promote cell metastasis by targeting CPEB4. Meanwhile, the level of CPEB4 could be used as a potential marker in NSCLC patients. Our findings unraveled novel functions of miR-1246 in lung cancer cells and shed light on NSCLC prognosis.