Search

Abstract Translation of upstream open reading frames (uORFs) typically abrogates translation of main (m)ORFs. The molecular mechanism of uORF regulation in cells is not well understood. Here, we data-mined human and mouse heart ribosome profiling analyses and identified a double-stranded RNA (dsRNA) structure within the GATA4 uORF that cooperates with the start codon to augment uORF translation and inhibits mORF translation. A trans-acting RNA helicase DDX3X inhibits the GATA4 uORF-dsRNA activity and modulates the translational balance of uORF and mORF. Antisense oligonucleotides (ASOs) that disrupt this dsRNA structure promote mORF translation, while ASOs that base-pair immediately downstream (i.e., forming a bimolecular double-stranded region) of either the uORF or mORF start codon enhance uORF or mORF translation, respectively. Human cardiomyocytes and mice treated with a uORF-enhancing ASO showed reduced cardiac GATA4 protein levels and increased resistance to cardiomyocyte hypertrophy. We further show the broad utility of uORF-dsRNA- or mORF-targeting ASO to regulate mORF translation for other mRNAs. This work demonstrates that the uORF-dsRNA element regulates the translation of multiple mRNAs as a generalizable translational control mechanism. Moreover, we develop a valuable strategy to alter protein expression and cellular phenotypes by targeting or generating dsRNA downstream of a uORF or mORF start codon.

This study shows that rather than high thermodynamic stability, specific length and structure enable regulatory mRNA stem-loops to pause translation. These findings aid identification of new regulatory mRNA stem-loops.

The ear leaf veins are an important transport structure in the maize "source" organ; therefore, the microscopic phenotypic characteristics and genetic analysis of the leaf veins are particularly essential for promoting the breeding of ideal maize varieties with high yield and quality. In this study, the microscopic image of the complete blade cross section was realized using X-ray micro-computed tomography (micro-CT) technology with a resolution of 13.5 µm. Moreover, the veins’ phenotypic traits in the cross section of the complete maize leaf, including the number of leaf veins, midvein area, leaf width, and density of leaf veins, were automatically and accurately detected by a deep-learning-integrated phenotyping pipeline. Then, we systematically collected vein phenotypes of 300 inbred lines at the silking stage of the ear leaves. It was found that the leaf veins’ microscopic characteristics varied among the different subgroups. The number of leaf veins, the density of leaf veins, and the midvein area in the stiff-stalk (SS) subgroup were significantly higher than those of the other three subgroups, but the leaf width was the smallest. The leaf width in the tropical/subtropical (TST) subgroup was the largest, but there was no significant difference in the number of leaf veins between the TST subgroup and other subgroups. Combined with a genome-wide association study (GWAS), 61 significant single-nucleotide polymorphism markers (SNPs) and 29 candidate genes were identified. Among them, the candidate gene Zm00001d018081 regulating the number of leaf veins and Zm00001d027998 regulating the midvein area will provide new theoretical support for in-depth analysis of the genetic mechanism of maize leaf veins.

Any surface immersed in sea water will suffer from marine fouling, including underwater sound absorption coatings. Traditional underwater sound absorption coatings rely heavily on the use of toxic, biocide-containing paints to combat biofouling. In this paper, an environmentally-friendly nanocomposite with integrated antifouling and underwater sound absorption properties was fabricated by adopting MWCNTs-COOH and SiO2 into PDMS at different ratios. SEM, FTIR and XPS results demonstrated MWCNTs were mixed into PDMS, and the changes in elements were also analyzed. SiO2 nanoparticles in PDMS decreased the tensile properties of the coating, while erosion resistance was enhanced. Antibacterial properties of the coatings containing MWCNTs-COOH and SiO2 at a ratio of 1:1, 1:3, and 1:5 reached 62.02%, 72.36%, and 74.69%, respectively. In the frequency range of 1500–5000 Hz, the average sound absorption coefficient of PDMS increased from 0.5 to greater than 0.8 after adding MWCNTs-COOH and SiO2, which illustrated that the addition of nanoparticles enhanced the underwater sound absorption performance of the coating. Incorporating MWCNTs-COOH and SiO2 nanoparticles into the PDMS matrix to improve its sound absorption and surface antifouling properties provides a promising idea for marine applications.

A current issue about causal attribution is whether people take simple contrast-factor attributions or complex joint attributions in contrast situations. For example, a stone does not dissolve in water and a piece of salt dissolves in water. That the piece of salt dissolves in water is due to: (A) the influence of the piece of salt; (B) the influence of the water; (C) the joint influence of the piece of salt and the water. We propose a mechanism-based sufficiency account for such questions. It argues that causal attributions are guided by mechanism-based explanatory sufficiency, and people prefer a mechanism-based attribution with explanatory sufficiency. This account predicts the sufficient joint attribution (the C option), whereas the conventional covariation approach predicts the contrast-factor attribution (the A option). Two experiments investigated whether contrast situations affect causal attributions for compound causation with explicit mechanism information and simple causation without explicit mechanism information, respectively. Both experiments found that in both the presence and absence of contrast situations, the majority of participants preferred sufficient joint attributions to simple contrast-factor attributions regardless of whether explicit mechanism information was present, and contrast situations did not affect causal attributions. These findings favor the mechanism-based sufficiency account rather than the covariation approach and the complexity account. In contrast situations, the predominance of joint attributions implies that explanatory complexity affects causal attributions by the modulation of explanatory sufficiency, and people prefer mechanism-based joint attributions that provide sufficient explanations for effects. The present findings are beyond the existing approaches to causal attributions.

Aim: To investigate the relationship between PI3K/Akt/NF-κB cellular signal pathway and the expression of P-gp and LRP in multidrug resistance (MDR) cell of nasopharyngeal carcinoma. Method: The PI3K, p-Akt and NF-κB/p65 as the activity of PI3K/Akt/NF-κB were detected by Western blot. The expressions of LRP and P-gp were detected by Western blot and real-time PCR. Result: The RIs of CNE/DDP group to DDP, 5-Fu, VCR, ADR and PTX were 35.04, 18.14, 24.13, 12.00 and 10.18, respectively. The RIs of LY-294002 group were 11.77, 5.83, 3.07, 3.86 and 3.34, and PDTC group were 11.08, 6.55, 7.66, 2.18 and 4.05. The expressions of PI3K, p-Akt and NF-κBp65, LRP and P-gp were increased and mRNA of LRP and P-gp were up-regulated in CNE/DDP. The expression of p-Akt in LY-294002 group was down-regulated. The expression of NF-κB p65 in PDTC group was decreased. The mRNA of LRP and P-gp in LY-294002 group and PDTC group were decreased. Conclusion: MDR of nasopharyngeal carcinoma cell can be regulated by activating PI3K/Akt/NF-κB signal pathway and then increase the expression of P-gp and LRP. The MDR of nasopharyngeal carcinoma cell can be reversed by inhibiting PI3K/Akt/NF-κB signal pathway. [ABSTRACT FROM AUTHOR]

Entanglement dynamics for a couple of two-level atoms interacting with independent structured reservoirs is studied using a non-perturbative approach. It is shown that the revival of atom entanglement is not necessarily accompanied by the sudden death of reservoir entanglement, and vice versa. In fact, atom entanglement can revive before, simultaneously or even after the disentanglement of reservoirs. Using a novel method based on the population analysis for the excited atomic state, we present the quantitative criteria for the revival and death phenomena. To give a more physically intuitive insight, the quasimode Hamiltonian method is applied. Our quantitative analysis is helpful for the practical engineering of entanglement. [ABSTRACT FROM AUTHOR]

Objective: To construct expression vectors of the fluorescent fusion proteins of all four human zona pellucida (ZP) genes respectively, and explore their expression in Chinese hamster ovary(CHO) cells and oocytes in vitro. Methods: The desired fluorescent protein sequence was inserted into a specific site of the zona pellucida gene sequence using the Gibson Assembly multi-fragment one-step splicing method to form the desired fusion gene fragment, and both ends of the fragment contained a specific sticky cleavage site of the entry vector. The entry vector pENTR 1A (no ccdB) and the fusion gene fragment were digested with a specific double enzyme, and the target gene fragment was ligated into the entry vector by T4 DNA ligase. Transfer genes from entry vector into destination vector via the LR reaction of the Gateway cloning technology. The plasmids validated by DNA sequencing were amplified and transfected into CHO cells. The expression of desired fusion protein was proved by RT-PCR and Western Blot. The distribution of target proteins in cytoplasm of CHO cells was visualized by laser confocal microscopy. Results: The expression vectors were successfully constructed, and the expression of each ZP protein in CHO cells was detected by RT-PCR and Western blot. The laser confocal microscopy revealed the distribution of ZP proteins. Conclusions: In this study, we successfully constructed fluorescent fusion protein expression plasmids of human zona pellucida genes, enabling the diagnosis of infertility caused by oocyte abnormalities.