22 research outputs found
Correction: The Roles of Arabidopsis CDF2 in Transcriptional and Posttranscriptional Regulation of Primary MicroRNAs.
Correction: The Roles of Arabidopsis CDF2 in Transcriptional and Posttranscriptional Regulation of Primary MicroRNAs
The Abnormal Expression of MicroRNA-542-3p in Hepatocellular Carcinoma and Its Clinical Significance
Aim. To evaluate the expression of miRNA-542-3p in hepatocellular carcinoma, establish its function, and evaluate whether it could serve as a biomarker for diagnosis and prognosis of HCC patients. Methods. qRT-PCR analysis was performed to determine the expression level of miRNA-542-3p in normal liver cells and HCC cell lines. Additionally, samples from TCGA consortium and from our patients were analyzed using biostatistical methods to ascertain whether miR-542-3p could be a good biomarker for HCC diagnosis and prognosis. The effects of miRNA-542-3p on HCC were investigated in HCCLM9 cells. Results. The expression of miRNA-542-3p in HCC cells was significantly downregulated compared with normal liver cells. A lower level of expression of miRNA-542-3p was found in HCC tissue samples than in adjacent normal liver tissue samples from TCGA cases and our patients. Further evaluation revealed that the downregulation was clearly related to aggressive clinicopathological characteristics and affected the prognosis, as low-expressing patients tended to have shorter overall survival. Moreover, cell assays revealed that miR-542-3p overexpression inhibited HCC cell growth and induced apoptosis. Conclusion. We demonstrated for the first time that miRNA-542-3p appears to function as a novel tumor suppressor in HCC and may serve as a promising prognostic biomarker in HCC patients
Field Distortion and Optimization of a Vapor Cell in Rydberg Atom-Based Radio-Frequency Electric Field Measurement
Highly excited Rydberg atoms in a room-temperature vapor cell are promising for developing a radio-frequency (RF) electric field (E-field) sensor and relevant measurement standards with high accuracy and sensitivity. The all-optical sensing approach is based on electromagnetically-induced transparency and Autler-Townes splitting induced by the RF E-field. Systematic investigation of measurement uncertainty is of great importance for developing a national measurement standard. The presence of a dielectric vapor cell containing alkali atoms changes the magnitude, polarization, and spatial distribution of the incident RF field. In this paper, the field distortion of rubidium vapor cells is investigated, in terms of both field strength distortion and depolarization. Full-wave numerical simulation and analysis are employed to determine general optimization solutions for minimizing such distortion and validated by measuring the E-field vector distribution inside different vapor cells. This work can improve the accuracy of atom-based RF E-field measurements and contributes to the development of related RF quantum sensors
The Roles of <i>Arabidopsis</i> CDF2 in Transcriptional and Posttranscriptional Regulation of Primary MicroRNAs
<div><p>The precise regulation of microRNA (miRNA) transcription and processing is important for eukaryotic development. Plant miRNAs are first transcribed as stem-loop primary miRNAs (pri-miRNAs) by RNA polymerase II,then cleaved in the nucleus into mature miRNAs by Dicer-like 1 (DCL1). We identified a cycling DOF transcription factor, CDF2, which interacts with DCL1 and regulates the accumulation of a population of miRNAs. CDF2 binds directly to the promoters of some miRNAs and works as a transcription activator or repressor for these miRNA genes. CDF2 binds preferentially to the pri-miRNAs regulated by itself and affects DCL1-mediated processing of these pri-miRNAs. Genetically, CDF2 works in the same pathway as miR156 or miR172 to control flowering. We conclude that CDF2 regulates a group of pri-miRNAs at both the transcriptional and posttranscriptional levels to maintain proper levels of their mature miRNAs to control plant development.</p></div
Microstructure and Magnetic Properties Dependence on the Sputtering Power and Deposition Time of TbDyFe Thin Films Integrated on Single-Crystal Diamond Substrate
As giant magnetostrictive material, TbDyFe is regarded as a promising choice for magnetic sensing due to its excellent sensitivity to changes in magnetic fields. To satisfy the requirements of high sensitivity and the stability of magnetic sensors, TbDyFe thin films were successfully deposited on single-crystal diamond (SCD) substrate with a Young’s modulus over 1000 GPa and an ultra-stable performance by radio-frequency magnetron sputtering at room temperature. The sputtering power and deposition time effects of TbDyFe thin films on phase composition, microstructure, and magnetic properties were investigated. Amorphous TbDyFe thin films were achieved under various conditions of sputtering power and deposition time. TbDyFe films appeared as an obvious boundary to SCD substrate as sputtering power exceeded 100 W and deposition time exceeded 2 h, and the thickness of the films was basically linear with the sputtering power and deposition time based on a scanning electron microscope (SEM). The film roughness ranged from 0.15 nm to 0.35 nm, which was measured by an atomic force microscope (AFM). The TbDyFe film prepared under a sputtering power of 100 W and a deposition time of 3 h possessed the coercivity of 48 Oe and a remanence ratio of 0.53, with a giant magnetostriction and Young’s modulus effect, suggesting attractive magnetic sensitivity. The realization of TbDyFe/SCD magnetic material demonstrates a foreseeable potential in the application of high-performance sensors
CDF2 acts as a transcription factor for some miRNA genes.
<p>(<b>A</b>) The relative levels of pri-miRNAs in Col, <i>cdf2</i>, <i>p35S</i>::<i>CDF2</i>/Col, <i>p35S</i>::<i>DCL1</i>/Col lines examined by real-time PCR. The relative fold changes were normalized to <i>ACTIN</i>. Data are given as means ± SD (n = 3). (<b>B</b>) ChIP-PCR analysis of five promoter fragments of miRNA genes in wild-type and <i>pCDF2</i>:<i>CDF2-YFP</i>/Col seedlings. ChIP assays were performed using the 22-day-old Col-0 and <i>pCDF2</i>::<i>CDF2-YFP</i>/Col seedlings expressing the CDF2-YFP fusion protein. DNA was amplified using primers specific to 6 miRNA promoter regions. (<b>C</b>) CHIP followed by real time PCR of 6 promoter fragments of miRNA genes in Col and <i>pCDF2</i>::<i>CDF2-YFP</i>/Col seedlings. Relative enrichment of fragments was calculated with HA antibodies as the control. Data are given as means ± SD (n = 3). (<b>D</b>) and (<b>E</b>) <i>pMIR172a</i>::<i>GUS</i> in Col, <i>cdf2</i> and <i>p35S</i>::<i>DCL1</i>/Col in seedlings (<b>D</b>) and flowers (<b>E</b>), respectively. Thirty plants containing GUS were analyzed for each of genotypes. (<b>F</b>) The transcript levels of GUS driven by <i>miR172b</i> promoter in Col, <i>cdf2</i> and <i>p35S</i>::<i>DCL1</i>/Col. GUS transcript levels were determined by qRT-PCR. Data are given as means ± SD (n = 3).</p
CDF2 interacts with DCL1.
<p>(<b>A</b>) Yeast two hybrid assays show the interactions between CDF2 and DCL1-RBD or HYL1. Co-transformed yeast colonies were spotted on the selective SC medium minus Trp and Leu, and then grown on SC medium minus His, Trp, and Leu supplemented with 5mM 3-amino-1, 2, 4-triazole (3-AT). (<b>B</b>) GST and MBP pull-down assays show the interaction between CDF2 and DCL1. (<b>C</b>) Co-IP assay shows the interaction between CDF2 and DCL1. The protein extracts from 22-day-old <i>Arabidopsis</i> plants coexpressing <i>pCDF2</i>::<i>CDF2-HA</i> and <i>pDCL1</i>::<i>DCL1-YFP</i> were incubated with anti-HA–conjugated agarose. The pellet was analyzed by immunoblotting with anti-HA and anti-GFP antibodies. (<b>D</b>) Bimolecular Fluorescence Complementation (BiFC) assays show that CDF2 or the C-terminal fragment of CDF2 (CDF2-C) interact with DCL1/HYL1 in D-bodies, while no interactions were observed between CDF2 and DCL1-9 or the N-terminal fragment of CDF2 (CDF2-N) and DCL1. Scale bar = 10μm. (<b>E</b>) Yeast two hybrid assays show that the C terminal fragment of CDF2 interacts with DCL1-RBD. C1, aa 189–457; C2, aa 271–457; C3, aa 360–457.</p
CDF2 suppresses the posttranscriptional processing of pri-miRNAs.
<p>(<b>A</b>) Northern blots show that overexpression of CDF2 reduce the accumulation of miRNAs indicated. (<b>B</b>) Northern blots show that the levels of miR156 and miR172 in <i>p35S</i>::miR156/Col and <i>p35S</i>::miR156/<i>cdf2</i> or <i>p35S</i>::miR172/Col and <i>p35S</i>::miR172/<i>cdf2</i> plants.</p