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RNA polymerase I (Pol I) is responsible for the synthesis of the majority of ribosomal RNA molecules in eukaryotes. Pol I subunit 12 (RPA12) is involved in the transcriptional termination and lipid metabolism in yeast. However, its role in human cells hasn't been investigated so far. Here, we show that RPA12 is present in the nucleolus and nucleoplasm of HeLa cells. RPA12 can act as a positive factor to regulate Pol I-mediated transcription and the proliferation of 293T and HeLa cells. Unexpectedly, RPA12 can repress HeLa cell migration, indicating that RPA12 plays opposite roles in cell proliferation and migration. This study provides a novel insight into the role of RPA12 in human cells.

Directed migration of neural stem cells (NSCs) is critical for embryonic neurogenesis and the healing of neurological injuries. LncRNA Pnky was reported to regulate neuronal differentiation of NSCs. However, its regulatory effect on NSC migration has never been explored. Herein, we identified that Pnky was also a key regulator of NSC migration, as underscored by the fact that Pnky silencing restrained the migration of both NSC lines C17.2 and NE4C, whereas Pnky over-expression promoted their migration. Meanwhile, Pnky regulated the expression of a core set of critical regulators that directing NSC migration, such as MMP2, MMP9, AKT and p38MAPK, etc. Through preliminary bioinformatics, we surprisingly noticed that splicing factors U2AF1 and U2AF1L4, as well as mRNA export adaptors SARNP, Aly/Ref and THOC7, were predicted to strongly interact with Pnky. Mechanically, Pnky could co-localize and directly bind to U2AF1, SARNP, Aly/Ref and THOC7, indicating the involvement of Pnky in modulating mRNA splicing and export processes. Collectively, our data delineated that, through interacting with U2AF1, SARNP, Aly/Ref and THOC7, Pnky coupled and modulated the mRNA splicing and export of downstream factors, which consequently affected NSC migration. These findings provide a possible theoretical basis of NSC migration for brain development and damage repair.

Directed migration of neural stem cells (NSCs) is critical for embryonic neurogenesis and the healing of neurological injuries. The long noncoding RNA (lncRNA) Pnky has been reported to regulate neuronal differentiation of NSCs by interacting with PTBP1. However, its regulatory effect on NSC migration remains to be determined. Herein, we identified that Pnky is also a key regulator of NSC migration in mice, as underscored by the finding that Pnky silencing suppressed but Pnky overexpression promoted the in vitro migration of both C17.2 and NE4C murine NSCs. Additionally, in vivo cell tracking demonstrated that Pnky depletion attenuated but Pnky overexpression facilitated the migration of NE4C cells in the spinal canal after transplantation via injection into the spinal canal. Mechanistically, Pnky regulated the expression of a core set of critical regulators that direct NSC migration, including MMP2, MMP9, Connexin43, Paxillin, AKT, ERK, and P38MAPK. Using catRAPID, a web server for large-scale prediction of protein-RNA interactions, the splicing factors U2AF1 and U2AF1L4, as well as the mRNA export adaptors SARNP, Aly/Ref, and THOC7, were predicted to interact strongly with Pnky. Further investigations using colocalization and RNA immunoprecipitation (RIP) assays confirmed the direct binding of Pnky to U2AF1, SARNP, Aly/Ref, and THOC7. Transcriptomic profiling revealed that as many as 5319 differential splicing events of 3848 genes, which were highly enriched in focal adhesion, PI3K-Akt and MAPK signaling pathways, were affected by Pnky depletion. The predominant subtype of differential splicing by Pnky depletion is intron retention, followed by alternative 5' and 3' splice sites and mutually exclusive exons. Moreover, Pnky knockdown substantially blocked but Pnky overexpression facilitated the export of MMP2, Paxillin, AKT, p38MAPK, and other mRNAs to the cytosol. Collectively, our data showed that through interacting with U2AF1, SARNP, Aly/Ref, and THOC7, Pnky couples and modulates the splicing and export of target mRNAs, which consequently controlling NSC migration. These findings provide a possible theoretical basis of NSC migration regulation.

Methanol oxidation reaction (MOR) efficiency is lowered by poor COads-tolerance and structural stability of Pt-based catalysts. Herein, single crystal Ni3S2 nanorods (with exposed {110} high-index ...

The synergies between transition metal oxides (bimetallic oxides) play important roles in determining the bifunctional catalytic activity for the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) in alkaline media. This study uses a facile hydrothermal method for uniformly coating CeO2 shells on the surfaces of ZIF-67-derived porous Co3O4@Z67-NT (T-temperature, 500–900 °C) cores. Co3O4@Z67-N700@CeO2 exhibits excellent bifunctional (ORR/OER) catalytic activity with a ΔE [Ej=10(OER) − E1/2(ORR)] of 0.70 V. For ORR, Co3O4@Z67-N700@CeO2 exhibits a higher half-wave potential of 0.88 V (vs. RHE) than that of commercial Pt/C (0.87 V), which is attributed to the synergies between CeO2 (Ce3+) and Co3O4 (Co2+). The oxygen vacancies on CeO2 can enhance O2 adsorption on the interfaces to promote the activation of adsorbed O2 to O2−, and can alleviate O2 deficiency during ORR, thereby improving ORR activity. For OER, Co3O4@Z67-N700@CeO2 has a lower overpotential of 350 mV at 10 mA cm−2 and a higher Faraday efficiency of 92.2% than those of RuO2. An effective valence transition between Ce3+ and Ce4+ endows CeO2 with high electrical conductivity and oxygen storage capacity, which greatly promote charge transfer and the generation/smooth transport of highly active species (O22−/O−). Moreover, the interactions between CeO2 (Ce3+/Ce4+ and oxygen vacancies) and Co3O4 (Co3+/CoOOH) provide more electrochemically active sites for OER. This study provides a new strategy for constructing the stable core@shell structure based on MOF derivatives to improve the ORR/OER performance.

RNA polymerase III (pol III) products play fundamental roles in a variety of cellular processes, including protein synthesis and cancer cell proliferation. In addition, dysregulation of pol III-directed transcription closely correlates with tumorigenesis. It is therefore of interest to identify novel pathways or factors governing pol III-directed transcription. Here, we show that transcription factor (TF) GATA binding protein 4 (GATA4) expression in SaOS2 cells was stimulated by the silencing of filamin A (FLNA), a repressor of pol III-directed transcription, suggesting that GATA4 is potentially associated with the regulation of pol III-directed transcription. Indeed, we show that GATA4 expression positively correlates with pol III-mediated transcription and tumor cell proliferation. Mechanistically, we found that GATA4 depletion inhibits the occupancies of the pol III transcription machinery factors at the loci of pol III target genes by reducing expression of both TFIIIB subunit TFIIB-related factor 1 and TFIIIC subunit general transcription factor 3C subunit 2 (GTF3C2). GATA4 has been shown to activate specificity factor 1 (Sp1) gene transcription by binding to the Sp1 gene promoter, and Sp1 has been confirmed to activate pol III gene transcription by directly binding to both Brf1 and Gtf3c2 gene promoters. Thus, the findings from this study suggest that GATA4 links FLNA and Sp1 signaling to form an FLNA/GATA4/Sp1 axis to modulate pol III-directed transcription and transformed cell proliferation. Taken together, these results provide novel insights into the regulatory mechanism of pol III-directed transcription.

The main issues regarding the practical application of microbial fuel cells (MFCs) are the poor activity and tolerance of oxygen reduction reaction (ORR) catalysts in wastewater. In this study, Auricularia chelated with Co, Fe and S ions is used as a nitrogen (N)-enriched carbon source to prepare N-doped bimetallic sulfide (Co

The sluggish kinetics of oxygen reduction reaction (ORR), especially in acid media, seriously restrains the commercialization of direct methanol fuel cells. Herein, we synthesize a hierarchical Co3O4@N-doped partly-graphitized carbon wrapped by Ti3+-self-doped TiO2 nanoparticles with multiple crystal-phases (anatase and rutile TiO2) as catalysts (Co3O4@NGC@MP-TiO2) for ORR in alkaline/acid media using ZIF-67 as a precursor. Co3O4@NGC@MP-TiO2-0.3 (tetrabutyl titanate of 0.3 mL) exhibits the same peak potential (Epeak of 0.83 V, vs. RHE) as Pt/C in 0.1 M KOH and the comparable Epeak (0.69 V) to Pt/C (0.7 V) in 0.5 M H2SO4. Synergistic effects between tetrahedral Co2+ (Co3O4) and Ti3+ (MP-TiO2) chiefly contribute to the high ORR activity. ORR stabilities of Co3O4@NGC@MP-TiO2-0.3 are higher than those of Pt/C in alkaline/acid media, attributing to that NGC@MP-TiO2 shell can protect active sites (tetrahedral Co2+ and N species) from corrosion and deactivation. Moreover, the dissociated adsorption of O2 on Ti3+ may facilitate the O2 protonation (Ti4+–OOHads−) to accelerate electron-transfer process and ORR kinetics in acid electrolyte, while acid-pickling of CoOx@NGC improves the stability of Co3O4@NGC to further smooth ORR process. This study provides a promising strategy for the design of highly-active and stable ORR catalysts in both alkaline and acid electrolytes.

Design of multi-hierarchical hybrid catalyst with high activity (bifunctional active-sites) is urgently needed by oxygen evolution/reduction reactions (OER/ORR). This study reports a feasible method for anchoring the copper oxide nanoparticles on the surface of Zeolitic Imidazolate Framework-67 derived cobalt oxide@nitrogen-doped graphitized carbon (Co3O4@NGC@CuO). For OER, Co3O4@NGC@CuO-0.6 (mass ratio of CuCl2·2H2O to Co3O4@NGC = 0.6) requires only 210 mV overpotential to achieve a current density of 10 mA cm−2 and a faraday efficiency of 93.5%. Owing to the synergies between CuO (Cu2+) shells and Co3O4 (Co2+/Co3+) cores, Cu2+ active sites can moderate the adsorption of oxygen-containing substances and balance the Co2+/Co3+ ratio. Tetrahedral Co2+ (Co2+Td) can be served as the active sites to induce the μ-OOH moieties (Octahedral Co3+, CoOOH) to enhance OER activity and stability. For ORR, Co3O4@NGC@CuO-0.6 has a half-wave potential of 0.865 V, comparable to that of commercial Pt/C (0.868 V). CuO with Cu2+/Cu+ can increase the O2 adsorption sites, while the active CoTd2+ sites can boost the breakage of O–O bonds to produce OH− via a 4e− ORR pathway. The bifunctional activity [ΔE = E10(OER)-E1/2(ORR)] of Co3O4@NGC@CuO-0.6 is only 0.58 V, confirming excellent ORR/OER activities. This study provides a promising strategy for constructing versatile active sites on catalysts.

Fabrication of efficient catalyst/co-catalyst for enhancing methanol oxidation and oxygen reduction reactions (MOR/ORR) is the key to make direct methanol fuel cells more economical. Here, hierarchical CoO@nitrogen-doped porous carbon@SnO2 (CoO@NPC@SnO2) polyhedrons are prepared as active catalysts for ORR and Pt supports/co-catalysts for MOR using zeolitic imidazolate frameworks-67 (ZIF-67). For ORR, CoO@NPC@SnO2-1 (Co@NPC-to-SnCl2·2H2O mass ratio of 1: 1) exhibits a more positive peak potential (0.82 V vs. RHE) than that of commercial Pt/C (10 wt.%). Outer SnO2 shells can prevent CoO cores (active tetrahedral Co2+) from corrosion during ORR. For MOR, Pt-CoO@NPC@SnO2-1 (5 wt.%) shows a much higher mass activity (1518 mA mgPt−1) than that of Pt/C (496.8 mA mgPt−1). High CO tolerance of Pt-CoO@NPC@SnO2-1 is attributed to strong metal (Pt)-metal oxides (SnO2) interactions, which facilitate adsorption of OH− on SnO2 to remove COads. Therefore, this study provides a strategy to enhance ORR/MOR performance by using hierarchically-structured catalysts/co-catalysts from ZIF templates.

Anodic electro-catalysis oxidation is a highly effective way to solve the pollution problem of antibiotics in wastewater and receiving water bodies. In this study, for the first time, molybdenum trioxide/Nano-graphite (MoO3/Nano-G) composites are synthesized as anodic catalysts by a surfactant-assisted solvothermal method followed by low-temperature calcination. The effects of the proportion of MoO3 to Nano-G (10, 30 and 50%) on the properties of composites are investigated through structural characterizations and electrochemical measurements. Results indicate that MoO3(30)/Nano-G electrode displays the electro-catalysis degradation efficiency of 99.9% towards ceftazidime, which is much higher than those of Nano-G (46.7%) and dimensionally stable anode (69.2%). The degradation mechanism for ceftazidime is studied by investigating the yields and kinds of active species. Results show that all of the OH, O2- and H2O2 are responsible for the electro-catalytic degradation process, and the produced OH radicals are the major active species for ceftazidime degradation. The synergistic effects between MoO3 and Nano-G greatly contribute to the activation of H2O molecules to produce OH, meanwhile the special sesame cake-like structure facilitates to the exposure of contaminants to OH on active sites to enhance the degradation efficiency. These results suggest that MoO3/Nano-G electrodes can be considered as the promising catalysts for treating bio-refractory organic wastewater.