Splicing factor TRA2A contributes to esophageal cancer progression via a noncanonical role in lncRNA m⁶A methylation

Transformer 2 alpha homolog (TRA2A), a member of the serine/arginine-rich splicing factor family, has been shown to control mRNA splicing in development and cancers. However, it remains unclear whether TRA2A is involved in lncRNA regulation. In the present study, we found that TRA2A was upregulated and correlated with poor prognosis in esophageal cancer. Downregulation of TRA2A suppressed the tumor growth in xenograft nude mice. Epitranscriptomic microarray showed that depletion of TRA2A affected global lncRNA methylation similarly to the key m6A methyltransferase, METTL3, by silencing. MeRIP-qPCR, RNA pull-down, CLIP analyses, and stability assays indicated that ablation of TRA2A reduced m6A-modification of the oncogenic lncRNA MALAT1, thus inducing structural alterations and reduced stability. Furthermore, Co-IP experiments showed TRA2A directly interacted with METTL3 and RBMX, which also affected the writer KIAA1429 expression. Knockdown of TRA2A inhibited cell proliferation in a manner restored by RBMX/KIAA1429 overexpression. Clinically, MALAT1, RBMX, and KIAA1429 were prognostic factors of worse survival in ESCA patients. Structural similarity-based virtual screening in FDA-approved drugs repurposed nebivolol, a β1-adrenergic receptor antagonist, as a potent compound to suppress the proliferation of esophageal cancer cells. Cellular thermal shift and RIP assay indicated that nebivolol may compete with MALAT1 to bind TRA2A. In conclusion, our study revealed the noncanonical function of TRA2A, which coordinates with multiple methylation proteins to promote oncogenic MALAT1 during ESCA carcinogenesis.</p

Identification of TiO₂ Polymorphs of the Bauxite Deposit in Central Guangxi by Laser Raman Spectroscopy

BACKGROUND: Rutile, anatase and brookite are TiO2 polymorphs. In the rutile in-situ U-Pb dating, rutile was determined primarily on electron microprobe data and cathodoluminescence images, while these methods sometimes could not effectively distinguish rutile, anatase and brookite. If there are a small number of the TiO2 polymorphs in the sample, the obtained age may be a mixed age with no significant geological significance. Therefore, the identification of TiO2 polymorphs is very important.OBJECTIVES: To identify TiO2 polymorphs from the bauxite deposit in central Guangxi.METHODS: TiO2 minerals in bauxite from central Guangxi were used as the research object, and laser Raman spectroscopy was applied to the identification of TiO2 isomorphic minerals.RESULTS: Four groups of laser Raman spectral lines with different characteristics were identified. The first three groups have laser Raman spectral peaks of anatase, rutile and brookite, respectively. The fourth group has two kinds of laser Raman spectral characteristic lines, one has both anatase characteristic peaks of 144, 198, 397, 513, 636cm-1 and rutile characteristic peaks of 442, 607cm-1, the other has both anatase characteristic peak of 144cm-1 and brookite characteristic peak of 153, 247, 325, 636cm-1.CONCLUSIONS:The TiO2 polymorphs of the bauxite deposit includs rutile, anatase, brookite and intermediate minerals that undergo phase transformation. The study indicates that the bauxite deposit in central Guangxi may have undergone a later regional metamorphism, leading to the transformation of TiO2 polymorphs. The laser Raman spectroscopy provides a new method for the identification of TiO2 polymorphs andrutile for in-situ U-Pb dating

Application of Microbeam Analytical Technology to Study the Occurrence of Cobalt from Copper-Cobalt Deposits

BACKGROUND: Microbeam analytical technology can be used to accurately analyze the petrography, morphology, structure, component and isotopic composition of ore minerals on the micro-nano scale, which plays a vital role in supporting the detailed research of geoscience.OBJECTIVES: To provide a practical technology for visually and quickly identifying the cobalt-bearing minerals and to understand the occurrence of cobalt in the Chambishi copper-cobalt deposit.METHODS: Microscopy was combined with microbeam analytical technologies of micro-XRF, EPMA, LA-ICP-MS to develop a method for quickly identifying the cobalt-bearing minerals from copper-cobalt deposits. First, representative thin sections were selected by polarized light microscopy, micro-XRF map scanning was then used to obtain the distribution characteristics of cobalt and combined elements in the thin sections. The polarized light microscopy was used again to identify independent cobalt minerals and cobalt-bearing minerals based on the characteristics of element distribution. Finally, the representative minerals were circled and the main and trace elements were determined by EPMA and LA-ICP-MS.RESULTS: The results showed that in the Chambishi Southeast orebody the cobalt not only existed in the form of independent minerals (pentlandite, linnaeite, carrollite), but also occurred in pyrite and pyrrhotite in the form of isomorphism, while the cobalt in the Chambishi West orebody mainly existed in the form of independent mineral-carrollite with a small amount.CONCLUSIONS: The combined microbeam analysis method is proposed to quickly and easily identify cobalt-bearing minerals and to study the occurrence of cobalt in the Chambishi Southeast orebody and Chambishi West orebody. It can effectively save the time of identifying minerals by traditional polarized light microscopy and avoid missing identification of some independent cobalt minerals or cobalt-bearing minerals with small particle size or without obvious optical characteristics

U–Pb dating and Hf isotope study of detrital zircons from the Zhifu Group, Jiaobei Terrane, North China Craton: Provenance and implications for Precambrian crustal growth and recycling

The Zhifu Group exposed in the northeastern Jiaobei Terrane is subdivided from base to top into the Laoyeshan, Bingying and Dongkou formations, and comprises mainly quartzites and muscovite- and tourmaline-bearing quartz schists. In order to define its provenance and depositional age, and to constrain the crustal growth and recycling of the source regions, we have conducted LA-ICP-MS U-Pb dating and in situ Hf isotopic study of detrital zircons from three quartz schists samples collected from the Zhifu Group. Most of the analyzed zircon grains have oscillatory zoning and Th/U ratios >0.4, suggesting igneous origins. 270 detrital zircons U-Pb analyses yield U-Pb ages of 1709-3679 Ma that cluster into three major age populations of 1.7-1.9 Ga with a peak at 1844 Ma, 1.9-2.0 Ga with a peak at 1936 Ma and 2.4-2.55 Ga with a peak at 2465 Ma, and two minor age populations of 2.2-2.35 and 2.6-2.7 Ga. The peaking age of 1844 Ma for the youngest age population indicates that the Zhifu Group must be deposited after 1844 Ma. Detrital zircons with ages of 1.7-2.35 Ga can be linked to pre- and post-tectonic polyphase magmatic events along the JLJB, and most of the zircons have negative epsilon(Hf(t)) values from +1.76 to -18.02 and two-stage Hf model ages (T-DM2) concentrating at similar to 2.7-3.0 Ga, indicating that source rocks of these zircons were derived from recycling of ancient crusts. Detrital zircons with ages of 2.4-2.9 Ga may have been sourced from the Archean granitoid (mainly TTG) gneisses in the Jiaobei Terrane, and these zircons have epsilon(Hf(t)) values from +6.4 to -7.53 and T-Dm2 of 2.6-3.4 Ga (peak at similar to 2.7-3.0 Ga), suggesting that source rocks of these zircons were mainly derived from juvenile crusts associated with a major crustal growth at similar to 2.7-3.0 Ga, and a limited amount of ancient crustal component. The two detrital zircons with ages of 3631 and 3679 Ma have negative epsilon(Hf(t)) values of -4.42 and -1.51 and T-Dm2 of 4137 and 4000 Ma, respectively, implying the recycling of ancient continental crust (>3.6 Ga) and crustal growth prior to 4.1 Ga in the NCC

Early Pleistocene integration of the Yellow River I: Detrital-zircon evidence from the North China Plain

International audienceThe Yellow River (YR) is one of the longest and most sediment-laden rivers in the world. However, the timing and mechanism of the integration of upstream and downstream reaches of the YR is still debated, with estimates ranging from >34 Ma to ~0.15 Ma. Here we address this debate by studying the detrital-zircon age spectra from three boreholes that penetrate late Miocene sediment in the lower YR floodplain. Our results show a significant provenance change between 1.6 and 1.5 Ma marking the input of new materials from the Middle Reach and/or the Upper Reach, suggesting the upstream and downstream parts of the YR were connected between 1.6 and 1.5 Ma. This late establishment of the YR is not consistent with the timing of uplift of the northeastern Tibetan Plateau and surrounding mountain ranges and thus precludes a tectonic control; however, it follows the Plio-Pleistocene onset of large-amplitude sea level changes, associated with a worldwide increase of fluvial incision. We propose that Plio-Pleistocene base level fluctuations likely triggered fluvial erosion propagating upstream from the YR lower reach and were thus the main driving force for river integration

Yellow River integration linked to Pleistocene increased climate instability

The establishment of major rivers in Asia is often attributed to tectonic-driven topography changes associated with Tibetan Plateau growth. However, it is unclear whether the globally accelerated erosion related to climatic instability since the Pliocene is an important mechanism for river evolution. Here we present detrital-zircon age data from three well-dated boreholes in the lower floodplain of the Yellow River (YR) to constrain the timing of the integration of the YR, one of the longest and the most sediment-laden rivers in the world. Our results show significant provenance change at 1.5 Ma corresponding to the final integration of the Upper and Middle Reaches to the Lower Reaches of YR, through the incision of the Sanmen Gorge. This late integration of the YR notably lags significant uplift of the northeastern Tibetan Plateau, precluding a tectonic driver. Our results rather suggest that Plio-Pleistocene increasing climate instability and sea level fall significantly enhanced headward incision finally cutting through the Sanmen Gorge to integrate the whole drainage system at 1.5 Ma