Lysine crotonylation on histones is a recently identified post-translational modification that has been demonstrated to associate with active promoters and to directly stimulate transcription. Given that crotonyl-CoA is essential for the acyl transfer reaction and it is a metabolic intermediate widely localized within the cell, we postulate that lysine crotonylation on nonhistone proteins could also widely exist. Using specific antibody enrichment followed by high-resolution mass spectrometry analysis, we identified hundreds of crotonylated proteins and lysine residues. Bioinformatics analysis reveals that crotonylated proteins are particularly enriched for nuclear proteins involved in RNA processing, nucleic acid metabolism, chromosome organization, and gene expression. Furthermore, we demonstrate that crotonylation regulates HDAC1 activity, expels HP1α from heterochromatin, and inhibits cell cycle progression through S-phase. Our data thus indicate that lysine crotonylation could occur in a large number of proteins and could have important regulatory roles in multiple nuclei-related cellular processes.

In this paper, we report on LA‐ICP‐MS zircon U–Pb dates of 14 Mesozoic volcanic rocks from the central Great Xing'an Range (CGXR). These data are integrated with the temporal and spatial distribution of local magmatism‐related Mesozoic mineralization, in an effort to develop an understanding of the geodynamic evolution of the region. Periodic magmatic events in the GXR date from ~1,703 through ~145 Ma. Mesozoic volcanism in the CGXR can be subdivided into three episodes: Triassic (250–205 Ma), Early–Middle Jurassic (182–165 Ma), and Late Jurassic–Early Cretaceous (155–115 Ma). A revision of the previously defined volcanic sequence is offered using a combination of our zircon U–Pb ages and published Mesozoic geological and geophysical evidence from northeast China. We propose that (a) Early–Middle Triassic volcanism in the CGXR resulted from subduction of the Paleo‐Asian oceanic plate; (b) Late Triassic volcanism was related to subduction of the Mongol–Okhotsk oceanic plate (especially near the Erguna Block) and subsequent extension after the closure of the Paleo‐Asian Ocean; (c) Early–Middle Jurassic volcanism was mainly controlled by the southward subduction of the Mongol–Okhotsk oceanic plate; (d) Late Jurassic–initial Early Cretaceous magmatism was initiated by closure of the Mongol–Okhotsk Ocean; and (e) late Early Cretaceous volcanism was induced following the final closure of the Mongol–Okhotsk Ocean and rollback of the Paleo‐Pacific oceanic plate.

This study presents new zircon U-Pb ages, Sr-Nd-Hf isotopic data, and whole-rock geochemical data obtained from the Early Cretaceous volcanic rocks from the north-western Great Xing'an Range, Northeast China, to constrain the late Mesozoic magmatism and geodynamic setting of this region, which is located in the eastern segment of the Central Asian Orogenic Belt (CAOB). Zircon U-Pb age determinations show that the studied samples formed at 124-114 Ma with an Early Cretaceous magmatic event produced voluminous felsic and minor mafic volcanic rocks. The mafic rocks are dominantly basalt and basaltic andesite, with relatively low SiO 2 contents (49.88-56.64 wt.%). These rocks are enriched in Th, U, large-ion lithophile elements (LILE; e.g., Rb, Ba, and K) and light rare-earth elements (REEs), and depleted in highfield-strength elements (HFSE; e.g., Nb, Ta, and Ti) and heavy REEs (Yb and Lu).The rocks have εNd(t) values of 0.44-0.75 and initial 87 Sr/ 86 Sr ratio of 0.70499-0.70548. These results indicate that the mafic rocks were derived from the partial melting of enriched lithospheric mantle that had been previously metasomatized by subduction-related fluids and experienced variable amounts of fractional crystallization and moderate crustal contamination. In contrast to the mafic rocks, the felsic rocks are dominantly peraluminous trachytes, rhyolites, and dacites with high SiO 2 contents and low MgO contents. These felsic rocks display enriched and variable concentrations of LILEs and REEs, show negative Eu anomalies, and have ε Hf (t) values of +2.6 to +8.3 with T DM2 ages of 1,014-655 Ma, indicating they were derived from partial melting of juvenile crustal materials. These Early Cretaceous igneous rock assemblages record a post-collisional lithospheric extensional setting resulting from the closure of the Mongol-Okhotsk Ocean, consistent with the results of previous studies on the contemporaneous tectono-magmatic activities in NE China.

No abstract

No abstract