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Flowering plants and mammals contain imprinted genes that are primarily expressed in the endosperm and placenta in a parent-of-origin manner. In this study, we show that early activation of the geminivirus genes C2 and C3 in Arabidopsis (Arabidopsis thaliana) plants, encoding a viral suppressor of RNA interference and a replication enhancer protein, respectively, is correlated with the transient vegetative expression of VARIANT IN METHYLATION5 (VIM5), an endosperm imprinted gene that is conserved in diverse plant species. VIM5 is a ubiquitin E3 ligase that directly targets the DNA methyltransferases MET1 and CMT3 for degradation by the ubiquitin-26S proteasome proteolytic pathway. Infection with Beet severe curly top virus induced VIM5 expression in rosette leaf tissues, possibly via the expression of the viral replication initiator protein, leading to the early activation of C2 and C3 coupled with reduced symmetric methylation in the C2-3 promoter and the onset of disease symptoms. These findings demonstrate how this small DNA virus recruits a host imprinted gene for the epigenetic activation of viral gene transcription. Our findings reveal a distinct strategy used by plant pathogens to exploit the host machinery in order to inhibit methylation-mediated defense responses when establishing infection.

Objective To summarize the clinical features of postoperative epileptic seizure in adults with moyamoya disease (MMD) treated with combined revascularization, and screen the related influencing factors. Methods Total 189 patients with MMD who underwent combined revascularization in Department of Neurosurgery of the First People's Hospital of Yunnan Province from January 2015 to June 2021 were included. Univariate and multivariate forward Logistic regression analysis was used to screen the influencing factors of epilepsy after combined revascularization in MMD patients. Results Logistic regression analysis showed preoperative seizure (OR = 5.523, 95%CI: 1.486-20.524; P = 0.011), revascularization bypass vessel located in frontal lobe (OR = 2.793, 95%CI: 1.027-7.597; P = 0.044), postoperative cerebral infarction (OR = 9.025, 95%CI: 2.121-38.404; P = 0.003), cerebral hyperperfusion syndrome (OR = 3.624, 95%CI: 1.281-10.253; P = 0.015) and intracranial hemorrhage (OR = 5.646, 95%CI: 1.219-26.142; P = 0.027) were the risk factors of postoperative epileptic seizure in patients with MMD. Conclusions Preoperative seizure, revascularization bypass vessel located in frontal lobe, postoperative cerebral infarction, cerebral hyperperfusion syndrome and intracranial hemorrhage are the clinical risk factors of epileptic seizure in adult MMD patients, timely intervention of risk factors may reduce postoperative epileptic seizure in patients with MMD.

In Arabidopsis, the 24-nucleotide (nt) small interfering RNAs (siRNAs) mediates RNA-directed DNA methylation (RdDM) and transcriptional gene silencing (TGS) of transposable elements (TEs). In the present study, we examined genome-wide changes in DNA methylation and siRNA accumulation in Arabidopsis induced by expression of the Cucumber mosaic virus silencing suppressor protein 2b known to directly bind to both the 21/24-nt siRNAs as well as their associated Argonaute proteins. We demonstrated a genome-wide reduction of CHH and CHG methylation in the 2b-transgenic plants. We found that 2b suppressed RdDM not only at the previously annotated loci directed by 24-nt siRNAs but also a new set of loci associated with 21/22-nt siRNAs. Further analysis showed that the reduced methylation of TEs and coding genes targeted by 21/22-nt siRNAs was associated with sequestration of the duplex siRNAs by the 2b protein but not with changes in either siRNA production or transcription. Notably, we detected both the deletion and/or the transposition of multicopy TEs associated with 2b-induced hypomethylation, suggesting potential TE reactivation. We propose that the silencing of many TEs in Arabidopsis is controlled by the 24- and 21-nt endogenous siRNAs analogous to Drosophila TE silencing by PIWI-interacting RNAs and siRNAs.

In Arabidopsis, the 24-nucleotide (nt) small interfering RNAs (siRNAs) mediates RNA-directed DNA methylation (RdDM) and transcriptional gene silencing (TGS) of transposable elements (TEs). In the present study, we examined genome-wide changes in DNA methylation and siRNA accumulation in Arabidopsis induced by expression of the Cucumber mosaic virus silencing suppressor protein 2b known to directly bind to both the 21/24-nt siRNAs as well as their associated Argonaute proteins. We demonstrated a genome-wide reduction of CHH and CHG methylation in the 2b-transgenic plants. We found that 2b suppressed RdDM not only at the previously annotated loci directed by 24-nt siRNAs but also a new set of loci associated with 21/22-nt siRNAs. Further analysis showed that the reduced methylation of TEs and coding genes targeted by 21/22-nt siRNAs was associated with sequestration of the duplex siRNAs by the 2b protein but not with changes in either siRNA production or transcription. Notably, we detected both the deletion and/or the transposition of multicopy TEs associated with 2b-induced hypomethylation, suggesting potential TE reactivation. We propose that the silencing of many TEs in Arabidopsis is controlled by the 24- and 21-nt endogenous siRNAs analogous to Drosophila TE silencing by PIWI-interacting RNAs and siRNAs.

Plant pathogenic fungi represent the largest group of disease-causing agents on crop plants, and are a constant and major threat to agriculture worldwide. Recent studies have shown that engineered production of RNA interference (RNAi)-inducing dsRNA in host plants can trigger specific fungal gene silencing and confer resistance to fungal pathogens1-7. Although these findings illustrate efficient uptake of host RNAi triggers by pathogenic fungi, it is unknown whether or not such an uptake mechanism has been evolved for a natural biological function in fungus-host interactions. Here, we show that in response to infection with Verticillium dahliae (a vascular fungal pathogen responsible for devastating wilt diseases in many crops) cotton plants increase production of microRNA 166 (miR166) and miR159 and export both to the fungal hyphae for specific silencing. We found that two V. dahliae genes encoding a Ca2+-dependent cysteine protease (Clp-1) and an isotrichodermin C-15 hydroxylase (HiC-15), and targeted by miR166 and miR159, respectively, are both essential for fungal virulence. Notably, V. dahliae strains expressing either Clp-1 or HiC-15 rendered resistant to the respective miRNA exhibited drastically enhanced virulence in cotton plants. Together, our findings identify a novel defence strategy of host plants by exporting specific miRNAs to induce cross-kingdom gene silencing in pathogenic fungi and confer disease resistance.

Objective To explore whether osteosarcoma cells can escape from cell senescence and reproduce, and to evaluate the oncogenic ability of senescent-escaped cells. To explain the mechanism of osteosarcoma recurrence from a new perspective. Methods Doxorubicin (DOX) was used to develop aging model of U2OS and MG63. Cell senescence was detected by SA-Gal staining and senescence-related molecules were detected by Western blot. The cells were replaced with DOX-free medium and cultured for 75 days. Cell proliferation and escape rate were measured by cell counting. Then they were divided into three groups: parent cell,senescent cell,escaped-senescence cell. Agarose cloning assay was used to detect cloning formation and nude mice tumorigenicity test was used to detect tumorigenicity. Results In DOX-induced U2OS or MG63 cells, senescence specific marker SA-β-Gal positive cells emerged 2-day after stimulation and reached the plateau on day 4 with more than 90% SA-β-Gal-positive cells. Effects of DOX on the activities of other SIPS-related regulators in OS cells were also measured at protein level and the expression of senescent regulators p-p53, p-Rb, and p-γ-H2AX were all increased significantly. Senescent OS cells were cultured in medium without DOX. The numbers of cells kept unchanged until day 75 and then began to increase (one-millionth of the escape rate). The reproducing cells gained even higher tumorigenic capability. Conclusions The senescent osteosarcoma cells escape from senescence and gain even higher tumorigenic capability to form new colonies eventually in recurrent tumor.

FeCrNiCoCuAlx (x=0, 1, 2, 3) high-entropy alloy (HEA) coatings were prepared on Q345 steel by laser cladding. The effects of Al content on microstructure and properties of FeCrNiCoCuAlx HEA coatings were studied by XRD, SEM and erosion wear tests. The results show that the HEA coatings are mainly composed by simple FCC and BCC solid-solution phases. With the increase of Al addition, the microstructure is evolved gradually from FCC to BCC. And the hardness of the HEA coatings improves significantly and the maximum value is 580HV. In 3.5%NaCl solution, the corrosion current density of FeCrNiCoCuAlx HEA coatings decreases firstly and then increases with the increase of Al addition. And the HEA coating has the best corrosion resistance at x=1. Meanwhile, the mass loss rate of HEA coating decreases in the erosion test when the impact angle is changed from 90° to 30°, exhibiting an erosion characteristic of ductile materials. The slurry erosion properties of the HEA coating increase with the increase of Al content, and the erosion wear mechanism is evolved from forging extrusion to ploughing and micro-cutting.