Filters








790 Hits in 2.0 sec

The HumanPOLD1Gene

Lingyun Zhao, Long-Sheng Chang
1997 Journal of Biological Chemistry  
The promoter of the human POLD1 gene encoding the catalytic subunit of DNA polymerase ␦ is G/C-rich and does not contain a TATA box. Transient transfection analysis in HeLa cells employing POLD1-luciferase chimeric plasmids revealed a core promoter region extending 328 base pairs (bp) from the major transcription initiation site. Multiple elements in this region including two 11-bp direct repeats located between nucleotide positions ؊92 and ؊22, play an important role in POLD1 promoter
more » ... Deletion or linker-replacement mutations of the repeats drastically reduced the promoter activity. A 70-bp DNA fragment containing the two repeats could stimulate the expression of the POLD1 or a heterologous promoter in an orientation-independent manner. DNase I footprinting and band-shift assays showed that HeLa nuclear extracts contained proteins specifically binding to the repeat sequences. Southwestern blot and UV cross-linking analyses identified Sp1 and two 85-kDa proteins that bound to the repeats. Additionally, screening of HeLa cDNA expression libraries for the sequence-specific DNA-binding protein using the 11-bp repeat sequences as the probe, identified a cDNA that corresponds to Sp3, a member of the Sp1 family. Cotransfection studies in Drosophila SL2 cells showed that both Sp1 and Sp3, but not Sp2, could activate the POLD1 promoter through the repeat sequences. The POLD1 promoter activity was induced about 4-fold at the late G 1 /S boundary in serum-stimulated cells. The 11-bp repeats together with an E2F-like sequence, located adjacent to the major transcription initiation site, were important for the stimulation. Taken together, this study provides a direct evidence for transcriptional regulation of the human POLD1 gene. The DNA replication of eukaryotic chromosomes is a complex but highly regulated process. Through the cooperation of multiple protein factors and enzymes including DNA polymerases, each chromosome replicates once during the S phase of the cell cycle (reviewed in Ref. 1) . Presently, the mechanisms underlying this cell cycle regulation of DNA replication are not completely understood. DNA polymerase ␦ (pol ␦) 1 is one of the major enzymes involved in the synthesis of mammalian nuclear DNA (2, 3). It was reported as a new type of DNA polymerase with an intrinsic 3Ј to 5Ј exonuclease activity (4), suggesting that it possesses exonucleolytic proofreading ability (5, 6). Purified pol ␦ is composed of a 125-kDa catalytic subunit and an associated 48-kDa small subunit whose function has not been defined (7). In addition, a 36-kDa factor was shown to convert the pol ␦ activity from low to high processivity (8). This factor was subsequently shown to be identical to the proliferating cell nuclear antigen (9, 10). Previously, we, in collaboration with Lee's group (11), and others (12) isolated the full-length cDNA for the catalytic subunit of human pol ␦. In addition, the coding sequences of the pol ␦ catalytic subunit have been isolated from bakers' yeast (13), fission yeast (14) , malaria parasite (15, 16), calf thymus (17) , and mouse cells (18) . Sequence analysis showed that the catalytic subunit of human pol ␦ contains 1,107 amino acids and is related to other eukaryotic DNA polymerases (11). Recently, we also cloned the gene for the catalytic subunit of human pol ␦ (POLD1) and its 5Ј-flanking sequences (19). The human POLD1 gene contains 27 exons and 26 introns. Transcription of the gene appears to be initiated at multiple sites with the major initiation site 53 nucleotides upstream of the ATG start codon. As found in the promoters of many mammalian housekeeping genes (for reviews, see , the POLD1 promoter is G/C-rich and does not contain a TATA box. Several potential binding sites for transcription factors AP2, CTF, Ets1, GCF, MBF-1, NF-E1, and Sp1 are present in the 5Ј-flanking region of the POLD1 gene (19). However, the significance of these elements in regulating POLD1 promoter activity is presently not known. Studies on the expression of the genes involved in nucleotide metabolism and DNA synthesis reveal the presence of multiple regulatory elements including the GC boxes, which are required for maximal promoter activity (23-30). The transcription factor Sp1 (31, 32) has been shown to regulate the transcription through the GC boxes. Recently, several Sp1-related proteins, Sp2, Sp3, and Sp4, that bind to the GC box or GT motif were identified (33-35); however, their role in promoter regulation is less defined. Sp3 and Sp4 share a high degree of amino acid sequence homology with Sp1 (33). The high degree of structural conservation among Sp1, Sp3, and Sp4 suggests that these transcriptional regulators act through binding to
doi:10.1074/jbc.272.8.4869 pmid:9030545 fatcat:n6hm2jyjbrgnll5yi37o5gtkly

Phytochemical, Antibacterial and Antioxidant Activity Evaluation of Rhodiola crenulata

Lingyun Zhong, Lianxin Peng, Jia Fu, Liang Zou, Gang Zhao, Jianglin Zhao
2020 Molecules  
The essential oil (EO) was successfully separated according to the method described by Zhao [39] , and stored at 4 °C in dark.  ...  The essential oil (EO) was successfully separated according to the method described by Zhao [39] , and stored at 4 • C in dark.  ... 
doi:10.3390/molecules25163664 pmid:32806502 fatcat:f3cezxcmzrc6ngwdzissuhll6y

Microfluidics for Medical Additive Manufacturing

Jie Wang, Changmin Shao, Yuetong Wang, Lingyun Sun, Yuanjin Zhao
2020 Engineering  
Compliance with ethics guidelines Jie Wang, Changmin Shao, Yuetong Wang, Lingyun Sun, and Yuanjin Zhao declare that they have no conflict of interest or financial conflicts to disclose.  ...  Zhao et al.  ...  Similarly, Zhao et al.  ... 
doi:10.1016/j.eng.2020.10.001 fatcat:kgxtwxtj75ecrbjyjxzwfffpfq

Photoresponsive Delivery Microcarriers for Tissue Defects Repair

Xin Zhao, Yuxiao Liu, Changmin Shao, Min Nie, Qian Huang, Jieshou Li, Lingyun Sun, Yuanjin Zhao
2019 Advanced Science  
Intelligent responsive microcarriers have emerged as a promising class of biomaterials for therapeutic delivery and tissue regeneration, since they can respond to external stimuli and release the loaded drugs in an active manner. Among various available stimuli, near-infrared (NIR) light is particularly attractive because it can penetrate biotic tissues with sufficient intensity and minimal damage. In this work, a kind of photoresponsive delivery microcarriers (PDMs) is developed using
more » ... dics. The microcarriers consist of NIR-absorbing graphene oxide, thermosensitive poly(N-isopropylacrylamide), and biocompatible gelatin methacrylate. Under NIR light, the PDMs exhibit an evident volume shrinkage and effectively trigger the drug release. After the NIR light is switched off, the shrunken microcarriers return to their original size. This reversible process can be stably repeated for many cycles. An in vitro experiment demonstrates that the NIR-radiated PDMs can actively release vascular endothelial growth factors and improve the tube formation of human umbilical vein endothelial cells. The results from the in vivo experiment also show an obvious photothermal effect and superior therapeutic efficacy of these PDMs in a rat model of tissue defects. These features make the PDMs an excellent drug delivery system and represent a great potential for clinical applications in tissue repair.
doi:10.1002/advs.201901280 pmid:31637165 pmcid:PMC6794614 fatcat:trgssd64znd47euqzgr3vomtyy

WiFi Energy-Harvesting Antenna Inspired by the Resonant Magnetic Dipole Metamaterial

Zhenci Sun, Xiaoguang Zhao, Lingyun Zhang, Ziqi Mei, Han Zhong, Rui You, Wenshuai Lu, Zheng You, Jiahao Zhao
2022 Sensors  
WiFi energy harvesting is a promising solution for powering microsensors and microsystems through collecting electromagnetic (EM) energies that exist everywhere in modern daily lives. In order to harvest EM energy, we proposed a metamaterial-inspired antenna (MIA) based on the resonant magnetic dipole operating in the WiFi bands. The MIA consists of two metallic split-ring resonators (SRRs), separated by an FR4 dielectric layer, in the broadside coupled configuration. The incident EM waves
more » ... e surface currents in the coupled SRRs, and the energy is oscillating between them due to near-field coupling. By varying the vertical distance of the two SRRs, we may achieve impedance matching without complicated matching networks. Collected EM energy can be converted to DC voltages via a rectifier circuit at the output of the coupling coil. Measured results demonstrate that the designed MIA may resonate at 2.4 GHz with a deep-subwavelength form factor (14 mm×14 mm×1.6 mm). The WiFi energy-harvesting capability of the proposed MIA with an embedded one-stage Dickson voltage multiplier has also been evaluated. A rectified DC voltage is approximately 500 mV when the MIA is placed at a distance of 2 cm from the WiFi transmit antenna with a 9 dBm transmitting power. The proposed compact MIA in this paper is of great importance for powering future distributed microsystems.
doi:10.3390/s22176523 pmid:36080982 pmcid:PMC9460457 fatcat:2xk4tqcdxbh6jahzg3ehgeud6i

Advances of "Click" Reaction Approach in Glycopolypeptide Synthesis

Zhao Wang, Lingyun Hao, Xiaojuan Zhang, Ruilong Sheng
2019 Youji huaxue  
Synthetic glycopolypeptides, as analogues of natural glycoproteins, are an emerging class of bioinspired polymers with excellent biocompatibility. They can mimic the structure and functions of natural glycoproteins, and show great potential for biological applications, such as biomolecular recognition, drug/gene delivery, cell adhesion and targeting, as well as cell culture and tissue engineering. Nevertheless, the efficient and lab/pilot scale preparation of well-defined and tunable glycopolyp
more » ... pti s with ompl x polym st u tu s, h s b n h ll nging fi l until now. h f st v lopm nt of " li k" h mistry/reaction offers versatile and powerful tools for the synthesis of glycopolypeptides. The state of arts for the development of new " li k" synth ti st t gi s n m tho s in th p p tion of gly opolyp pti s, m inly in lu ing post-polymerization glycosylation of synthetic polypeptides and ring-opening polymerization of glycosylated N-carboxyanhydride (glyco-NCA) is reviewed. The pros and cons of current developments for the synthesis of glycopolypeptide analogues and their future perspectives are also stated and discussed.
doi:10.6023/cjoc201903038 fatcat:rx3ltyu3zbdiviztsoiam7j4fi

Review on Metasurfaces: An Alternative Approach to Advanced Devices and Instruments

Xiaoguang Zhao, Zhenci Sun, Lingyun Zhang, Zilun Wang, Rongbo Xie, Jiahao Zhao, Rui You, Zheng You
2022 Advanced Devices & Instrumentation  
Recently, in order to circumvent the image blurring in underwater detection, Zhao et al. developed a metalens-based polarization imaging instrument assisted by the differences of polarization states between  ... 
doi:10.34133/2022/9765089 fatcat:6tckabphxbfgvncwprlv5cnzty

Metal-phenolic networks: facile assembled complexes for cancer theranostics

Wensheng Xie, Zhenhu Guo, Lingyun Zhao, Yen Wei
2021 Theranostics  
In recent years, metal-phenolic networks (MPNs) have attracted increasing attention for the engineering of multi-functional platforms because of their easy fabrication processes, excellent physicochemical properties, outstanding biocompatibility, and promising theranostic applications. In this review, we summarize recent progress in the design, synthesis, shape-control, biocompatibility evaluation, and potential theranostic applications of MPNs, especially for cancer theranostics. First, we
more » ... ide an overview of various MPN systems, relevant self-assembly procedures, and shape-controllable preparation. The in vitro and in vivo biocompatibility evaluation of MPNs is also discussed, including co-incubation viability, adhesion, bio-distribution, and inflammation. Finally, we highlight the significant achievements of various MPNs for cancer theranostics, such as tumor imaging, drug delivery, photothermal therapy, radiotherapy, and chemo- and photo-dynamic therapy. This review provides a comprehensive background on the design and controllable synthesis, in vitro and in vivo biocompatibility evaluation, applications of MPNs as cancer theranostic agents, and presents an overview of the most up-to-date achievements in this field.
doi:10.7150/thno.58711 pmid:33995665 pmcid:PMC8120219 fatcat:7yvbyfxe3rgurfpqjvt3y4xbke

A BERT based Sentiment Analysis and Key Entity Detection Approach for Online Financial Texts [article]

Lingyun Zhao, Lin Li, Xinhao Zheng
2020 arXiv   pre-print
The emergence and rapid progress of the Internet have brought ever-increasing impact on financial domain. How to rapidly and accurately mine the key information from the massive negative financial texts has become one of the key issues for investors and decision makers. Aiming at the issue, we propose a sentiment analysis and key entity detection approach based on BERT, which is applied in online financial text mining and public opinion analysis in social media. By using pre-train model, we
more » ... t study sentiment analysis, and then we consider key entity detection as a sentence matching or Machine Reading Comprehension (MRC) task in different granularity. Among them, we mainly focus on negative sentimental information. We detect the specific entity by using our approach, which is different from traditional Named Entity Recognition (NER). In addition, we also use ensemble learning to improve the performance of proposed approach. Experimental results show that the performance of our approach is generally higher than SVM, LR, NBM, and BERT for two financial sentiment analysis and key entity detection datasets.
arXiv:2001.05326v1 fatcat:juwmnfnfsfa5ddp4zzh7vfnwz4

Advances in enzyme-catalysis-mediated RAFT polymerization

Wensheng Xie, Lingyun Zhao, Yen Wei, Jinying Yuan
2021 Cell Reports Physical Science  
Enzyme-catalysis-mediated reversible addition-fragmentation chain transfer (Enz-RAFT) polymerization is considered to be one of the most versatile synthetic strategies and biotechnologies, proceeding in an efficient, mild, and selective manner. Benefiting from its benignity, high efficiency, and eco-friendliness, Enz-RAFT has been widely applied in various fields, such as precise, multi-block copolymers; ultrahigh molecular weight (UHMW) polymers; functional polymers with complex architectures;
more » ... and well-defined polymers. Different from other new RAFT polymerization techniques (e.g., metal-, photo-, redox-, photoinduced electron/energy transfer [PET]-, etc.), Enz-RAFT can initiate RAFT polymerization under ambient conditions, particularly controlling the RAFT process even in the present of oxygen, which has attracted much attention. This review summarizes current advances in Enz-RAFT polymerization for functional applications. Figure 6. HRP mediated three different catalytic reactions (RAFT polymerization, thiol-ene, and Diels-Alder reactions) Reprinted with permission from Lu et al. (2018). 42 Review physiochemical and biomedical properties and providing a solution for investigating structure-activity relationships. Similarly, Danielson et al. 41 used HRP as a free-radical generator for the RAFT equilibrium to develop well-defined homopolymers. The successful RAFT polymerization of N,N-dimethylacrylamide showed a high conversion rate of 92% and a narrow molecular-weight distribution, with dispersity values between 1.1 and 1.3. Meanwhile, the enzymatic activity after polymerization retained about 75% compared with the original activity. Further polymerization of poly(N-isopropylacrylamide), Figure 7. P2Ox-HRP cascade catalysis for RAFT polymerization Reprinted with permission from Liu et al. (2017). 44
doi:10.1016/j.xcrp.2021.100487 fatcat:kyrbzqyd2ffcfiyisnuvgunfey

Effects of Yeast Polysaccharide on Growth and Flavonoid Accumulation in Fagopyrum tataricum Sprout Cultures

Gang Zhao, Jianglin Zhao, Lianxin Peng, Liang Zou, Jingbo Wang, Lingyun Zhong, Dabing Xiang
2012 Molecules  
The purpose of this study was to investigate the effects of yeast polysaccharide (YPS) on growth and flavonoid accumulation in sprout cultures of Fagopyrum tataricum (tartary buckwheat). Without obvious change in the appearance of the sprouts, the exogenous YPS notably stimulated the production of functional metabolites in F. tataricum sprouts, and the stimulation effect was concentration-dependent. With 400 mg/L of YPS applied to the sprout cultures on day 6, the total rutin and quercentin
more » ... ent was effectively increased to 42.8 mg/gdw, or about 1.4-fold in comparison with the control of 31.2 mg/gdw. Feeding with 800 mg/L of YPS on day 9, the sprouts biomass was increased by about 8% compared to the control culture (0.99 gdw/100 sprouts versus 0.92 gdw/100 sprouts). Moreover, the present study revealed that the accumulation of these bioactive metabolites resulted from the stimulation of the phenylpropanoid pathway by YPS treatment. It could be an effective strategy for improving the functional quality of the F. tataricum sprouts provided with YPS.
doi:10.3390/molecules171011335 pmid:23011276 fatcat:6cyffpgov5fvfp5egvnm3kd4jy

Synthesis and Properties of MPEG-Coated Superparamagnetic Magnetite Nanoparticles

Xueli Cao, Baolin Zhang, Fangyuan Zhao, Lingyun Feng
2012 Journal of Nanomaterials  
The magnetite nanoparticles were synthesized by the thermal decomposition of iron(III) acetylacetonate in methoxy polyethylene glycol, which was used as solvent, reducing agent, and modifying agent in the reaction. The morphologies and phase compositions of the nanoparticles were determined by transmission electron microscopy and X-ray diffraction, respectively. The surface coating of the nanoparticles was recognized using Fourier transform infrared spectroscopy. Magnetic properties were
more » ... d using superconducting quantum interference device. The zeta potential and hydrodynamic size of the nanoparticles was determined using nanoparticle and zeta potential analyzer. The magnetite nanoparticles show superparamagnetic behavior in 300 K. The negatively charged methoxy polyethylene glycol-coated magnetite nanoparticles in water exhibited longer-time dispersion with small hydrodynamic size than the magnetite nanoparticles synthesized by the thermal decomposition of iron(III) acetylacetonate in polyethylene glycol. The less conjunction between methoxy polyethylene glycol-coated magnetite nanoparticles due to the inert –CH3terminal group may cause their higher stability in water dispersion.
doi:10.1155/2012/607296 fatcat:jtsypig6mzcfbjmqk5ev2pfnbe

TUMK-ELM: A Fast Unsupervised Heterogeneous Data Learning Approach

Lingyun Xiang, Guohan Zhao, Qian Li, Wei Hao, Feng Li
2018 IEEE Access  
ZHAO received the B.E. degree in electronic information engineering from Hunan Normal University, Hunan, China, in 2012.  ... 
doi:10.1109/access.2018.2847037 fatcat:eqbwkjgp35bolflrnbfuiohjim

Zhao_Supplementary Materials Combined_Rev2.pdf from Long-lasting vocal plasticity in adult marmoset monkeys

Lingyun Zhao, Bahar Boroumand Rad, Xiaoqin Wang
2019 Figshare  
Supplementary text, tables and figures
doi:10.6084/m9.figshare.8313275 fatcat:vqjozqfbvvdbhkhjzv2zuo3wlu

Zhao_Supplementary Materials Combined_Rev2.pdf from Long-lasting vocal plasticity in adult marmoset monkeys

Lingyun Zhao, Bahar Boroumand Rad, Xiaoqin Wang
2019 Figshare  
Supplementary text, tables and figures
doi:10.6084/m9.figshare.8256113 fatcat:zz56lwedr5aunlfia3aeixok34
« Previous Showing results 1 — 15 out of 790 results