In this work, the electrical properties of AlGaN/GaN heterostructure grown on Si substrate with low-temperature AlN (LT-AlN) interlayers were investigated. Hall effect measurement was used to test the electrical properties of AlGaN/GaN heterostructure in all samples with different LT-AlN thickness. It is showed that the thickness of low-temperature AlN interlayers in the bufferlayer obviously effect the electrical properties of two-dimensional electron gas (2DEG) in the heterostructure channel. The sample with 15 nm LT-AlN interlayers reached the maximum electron mobility of 4090 cm 2 /Vs. Combined with XRD and AFM measurements, it is found that the dislocation density, surface roughness and stress conditions determined the electrical properties of 2DEG.
Abstract LINC00624 is a long noncoding RNA (lncRNA) which was seldom investigated before. The goal of our study is to clarify the expression and underlying network of LINC00624 in hepatocellular carcinoma (HCC). Here, both HCC and normal living cell lines were employed. Real‐time quantitative PCR and western blot were used to determine the pattern of genes and proteins. Colony formation, flow cytometry and western blot tests were used to determine cell proliferation and apoptosis, respectively. Dual luciferase was used to verify molecule‐molecule interactions. LINC00624 expression was increased in HCC cell lines and miR‐342‐3p was decreased. Elimination of LINC00624 increased proliferation while decreasing cell apoptosis. LINC00624 acted as a molecular sponge for miR‐342‐3p, hence facilitating DNAJC5 expression. Functional tests demonstrated that miR‐342‐3p suppression could reverse the effect of LINC00624 silence and overexpression of DNAJC5 significantly mitigated the biological consequences of miR‐342‐3p. These finding demonstrated that LINC00624 aggravated HCC progression by modulating proliferation and apoptosis via targeting miR‐342‐3p/DNAJC5 axis. These data support that inhibition of LINC00624 may a potential treatment strategies of HCC.
Transposons are generally kept silent by epigenetic mechanisms including DNA methylation. Here, we identified a pair of H arbinger transposon-derived proteins (HDPs), HDP1 and HDP2, as anti-silencing factors in Arabidopsis. hdp1 and hdp2 mutants displayed an enhanced silencing of transgenes and some transposons. Phylogenetic analyses revealed that HDP1 and HDP2 were co-domesticated from the Harbinger transposon-encoded transposase and DNA-binding protein, respectively. HDP1 interacts with HDP2 in the nucleus, analogous to their transposon counterparts. Moreover, HDP1 and HDP2 are associated with IDM1, IDM2, IDM3 and MBD7 that constitute a histone acetyltransferase complex functioning in DNA demethylation. HDP2 and the methyl-DNA-binding protein MBD7 share a large set of common genomic binding sites, indicating that they jointly determine the target specificity of the histone acetyltransferase complex. Thus, our data revealed that HDP1 and HDP2 constitute a functional module that has been recruited to a histone acetyltransferase complex to prevent DNA hypermethylation and epigenetic silencing.
Phytohormone auxin plays a vital role in plant development and responses to environmental stresses. The spatial and temporal distribution of auxin mainly relies on the polar distribution of the PIN-FORMED (PIN) auxin efflux carriers. In this study, we dissected the functions of OsPIN9, a monocot-specific auxin efflux carrier gene, in modulating chilling tolerance in rice. The results showed that OsPIN9 expression was dramatically and rapidly suppressed by chilling stress (4°C) in rice seedlings. The homozygous ospin9 mutants were generated by CRISPR/Cas9 technology and employed for further research. ospin9 mutant roots and shoots were less sensitive to 1-naphthaleneacetic acid (NAA) and N-1-naphthylphthalamic acid (NPA), indicating the disturbance of auxin homeostasis in the ospin9 mutants. The chilling tolerance assay showed that ospin9 mutants were more tolerant to chilling stress than wild-type (WT) plants, as evidenced by increased survival rate, decreased membrane permeability, and reduced lipid peroxidation. However, the expression of well-known C-REPEAT BINDING FACTOR (CBF)/DEHYDRATION-RESPONSIVE ELEMENT-BINDING PROTEIN 1 (DREB)-dependent transcriptional regulatory pathway and Ca2+ signaling genes was significantly induced only under normal conditions, implying that defense responses in ospin9 mutants have probably been triggered in advance under normal conditions. Histochemical staining of reactive oxygen species (ROS) by 3'3-diaminobenzidine (DAB) and nitroblue tetrazolium (NBT) showed that ospin9 mutants accumulated more ROS than WT at the early stage of chilling stress, while less ROS was observed at the later stage of chilling treatment in ospin9 mutants. Consistently, antioxidant enzyme activity, including catalase (CAT), peroxidase (POD), and superoxide dismutase (SOD), improved significantly during the early chilling treatments, while was kept similar to WT at the later stage of chilling treatment, implying that the enhanced chilling tolerance of ospin9 mutants is mainly attributed to the earlier induction of ROS and the improved ROS scavenging ability at the subsequent stages of chilling treatment. In summary, our results strongly suggest that the OsPIN9 gene regulates chilling tolerance by modulating ROS homeostasis in rice.
Significance How heterochromatin affects RNA processing is unclear. The chromatin regulators ASI1 and EDM2 function in regulating alternative polyadenylation at genes with intronic heterochromatin. We found that ASI1 and EDM2 are associated in planta through interactions with a putative RNA-binding protein, AIPP1. Protein interaction assays suggest that the RNA Pol II C-terminal domain phosphatase CPL2 and two other proteins (AIPP2 and AIPP3) are associated with the ASI1-AIPP1-EDM2 complex. Like ASI1 and EDM2, AIPP1 also functions in promoting the expression of heterochromatin-containing genes. However, the function of CPL2, AIPP2, and AIPP3 is antagonistic to that of ASI1, EDM2, and AIPP1. Our discovery of the ASI1-AIPP1-EDM2 complex and associated proteins is important for understanding how heterochromatin regulates RNA processing.
Abstract Background Tall fescue ( Festuca arundinacea Schreb.) is a major cool-season forage and turfgrass species. The low tiller density and size dramatically limits its turf performance and forage yield. MicroRNAs (miRNA)-genes modules play critical roles in tiller development in plants. In this study, a genome-wide small RNA profiling was carried out in two tall fescue genotypes contrasting for tillering production (‘Ch-3’, high tiller production rate and ‘Ch-5’, low tiller production rate) and two types of tissue samples at different tillering development stage (Pre-tillering, grass before tillering; Tillering, grass after tillering). ‘Ch-3’, ‘Ch-5’, Pre-tillering, and Tillering samples were analyzed using high-throughput RNA sequencing. Results A total of 222 million high-quality clean reads were generated and 208 miRNAs were discovered, including 148 known miRNAs belonging to 70 families and 60 novel ones. Furthermore, 18 miRNAs were involved in tall fescue tiller development process. Among them, 14 miRNAs displayed increased abundance in both Ch-3 and Tillering plants compared with that in Ch-5 and Pre-tillering plants and were positive with tillering, while another four miRNAs were negative with tiller development. Out of the three miRNAs osa-miR156a, zma-miR528a-3p and osa-miR444b.2, the rest of 15 miRNAs were newfound and associated with tiller development in plants. Based on our previous full-length transcriptome analysis in tall fescue, 28,927 potential target genes were discovered for all identified miRNAs. Most of the 212 target genes of the 18 miRNAs were dominantly enriched into “ubiquitin-mediated proteolysis”, “phagosome”, “fatty acid biosynthesis”, “oxidative phosphorylation”, and “biosynthesis of unsaturated fatty acids” KEGG pathways. In addition, bdi-miR167e-3p targets two kinase proteins EIF2AK4 and IRAK4, and osa-miR397a targets auxin response factor 5, which may be the significant miRNA-genes controllers in tillering development. Conclusions This is the first genome-wide miRNA profiles analysis to identify regulators involved in tiller development in cool-season turfgrass. Tillering related 18 miRNAs and their 212 target genes provide novel information for the understanding of the molecular mechanisms of miRNA-genes mediated tiller development in cool-season turfgrass.
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