Publications by authors named "Xiaoze Li"

11 Publications

  • Page 1 of 1

Development of a compact coaxial cusped periodic permanent magnet focusing system.

Rev Sci Instrum 2020 Oct;91(10):104703

Department of Engineering Physics, Tsinghua University, Beijing 100084, China.

To achieve the application of a periodic permanent magnet in high power microwave, a compact coaxial cusped periodic permanent magnet (CPPM) focusing system is constructed. The system consists of permanent magnets with different magnetization directions and soft magnets. Taking the required magnetic field performance and the effect of demagnetization into account, NdFeB and FeCoV are selected as the permanent and soft magnet materials. After the system is constructed, the magnetic field is measured. The results show that the guiding magnetic field strength and period of the CPPM are about 0.29 T and 26 mm, respectively, and the magnetic field distribution of measurement shows good agreement with the simulation results. However, there are some differences between the measurement and simulation results, and the differences are compared and analyzed here.
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http://dx.doi.org/10.1063/5.0025010DOI Listing
October 2020

Spectrum of PAH gene mutations and genotype-phenotype correlation in patients with phenylalanine hydroxylase deficiency from Shanxi province.

Brain Dev 2021 Feb 4;43(2):220-229. Epub 2020 Sep 4.

Medical Genetic Center, Changzhi Maternal and Child Health Care Hospital, 38 Weiyuanmen Road, Changzhi, Shanxi 046000, China. Electronic address:

Background: Phenylalanine hydroxylase deficiency (PAHD) is an autosomal recessive inborn error that affects phenylalanine (Phe) metabolism. It has a complex phenotype with many variants and genotypes among different populations. Shanxi province is a high-prevalence area of PAHD in China.

Methods: In this study, eighty-nine PAHD patients were subjected to genetic testing using Sanger sequencing, followed by multiplex ligation-dependent probe amplification analysis (MLPA). Allelic and genotypic phenotype values (APV and GPV, respectively) were used for genotype-based phenotypic prediction.

Results: Fifty-one types of variants, including three novel forms, were identified. The predominant variant was p.R243Q (22.09%), followed by p.R53H (10.47%), p.EX6-96A > G (9.30%), p.V399V (5.23%) and p.R413P (3.49%). Notably, mild hyperphenylalaninemia (MHP) has a high prevalence in this region (up to 45.76%), and the variant p.R53H was solely observed in patients of MHP. According to the genotype-phenotype prediction, the APV/GPV system was well correlated with the metabolic phenotype of most PAHD patients.

Conclusion: We have systematically constructed the mutational and phenotypic spectrum of PAH in Shanxi province. Hence, this study will help to further understand the genotype-phenotype associations in PAHD patients, and it may offer more reliable genetic counseling and management.
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http://dx.doi.org/10.1016/j.braindev.2020.08.012DOI Listing
February 2021

Identification of a novel homozygous nonsense variant in a Chinese patient with ethylmalonic encephalopathy and a genotype-phenotype spectrum review.

Clin Chim Acta 2020 Oct 30;509:8-17. Epub 2020 May 30.

Medical Genetic Center, Changzhi Maternal and Child Health Care Hospital, 38 Weiyuanmen Road, Changzhi, Shanxi 046000, China. Electronic address:

Ethylmalonic encephalopathy (EE) is a rare and devastating neurodegenerative disease caused by mutations in the ETHE1 gene. It is characterized by early-onset encephalopathy, chronic diarrhea, petechiae, orthostatic acrocyanosis, and high levels of methylsuccinic, lactic, and ethylmalonic acids in body fluids. In this study, we report a patient with EE, who was identified through newborn screening, and the diagnosis was confirmed by targeted next-generation sequencing (NGS). The patient displayed recurrent petechiae, intermittent jaundice, protracted diarrhea, and extensive developmental regression. Genetic testing identified a homozygous nonsense variant, c.295C > T (p. Q99*), in the ETHE1 gene. A review of all known ETHE1 variants observed in other EE patients was conducted. This revealed the current difficulties in EE diagnosis. Besides, it also showed that patients with truncated variants of ETHE1 might exhibit pathological symptoms earlier and present more severe manifestations. Finally, a novel nonsense variant was identified, which supported and expanded our current knowledge of the variant spectrum for ETHE1. This novel variant also deepened our understanding of the genotype-phenotype associations that occur in EE patients.
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http://dx.doi.org/10.1016/j.cca.2020.05.051DOI Listing
October 2020

Graphitic Carbon Nitride Nanosheets Decorated Flower-like NiO Composites for High-Performance Triethylamine Detection.

ACS Omega 2019 Jun 3;4(6):9645-9653. Epub 2019 Jun 3.

The Collaboration Innovation Center of Coal Safety Production of Henan Province, College of Chemistry and Chemical Engineering, and College of Safety Science and Engineering, State Key Laboratory Cultivation Base for Gas Geology and Gas Control, Henan Polytechnic University, Jiaozuo 454000, P. R. China.

The graphitic carbon nitride (g-CN) nanosheets decorated three-dimensional hierarchical flower-like nickel oxide (NiO) composites (NiO/g-CN, Ni/CN) were synthesized via a facile hydrothermal method combined with a subsequent annealing process. The structure and morphology of the as-prepared Ni/CN composites were characterized by X-ray diffraction, field-emission scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, and nitrogen absorption. The gas-sensing experiments reveal that the composites with 10 wt % two-dimensional g-CN (Ni/CN-10) not only exhibits the highest response of 20.03 that is almost 3 times higher than pristine NiO to 500 ppm triethylamine (TEA) at the optimal operating temperature of 280 °C but also shows a good selectivity toward TEA. The gas-sensitivity promotion mechanism is attributed to the internal charge transfer within the p-n heterojunction. Furthermore, the high specific surface area of the Ni/CN composites promotes adequate contact and reaction between the composites and triethylamine molecules. Therefore, the Ni/CN sensor has a great potential application in detecting TEA.
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http://dx.doi.org/10.1021/acsomega.9b00905DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6648768PMC
June 2019

The Concerted Action of E2-2 and HEB Is Critical for Early Lymphoid Specification.

Front Immunol 2019 18;10:455. Epub 2019 Mar 18.

Department of Laboratory Medicine, Center for Hematology and Regenerative Medicine, Karolinska Institutet, Stockholm, Sweden.

The apparition of adaptive immunity in correlates with the expansion of the E-protein family to encompass E2-2, HEB, and E2A. Within the family, E2-2 and HEB are more closely evolutionarily related but their concerted action in hematopoiesis remains to be explored. Here we show that the combined disruption of E2-2 and HEB results in failure to express the early lymphoid program in Common lymphoid precursors (CLPs) and a near complete block in B-cell development. In the thymus, Early T-cell progenitors (ETPs) were reduced and T-cell development perturbed, resulting in reduced CD4 T- and increased γδ T-cell numbers. In contrast, hematopoietic stem cells (HSCs), erythro-myeloid progenitors, and innate immune cells were unaffected showing that E2-2 and HEB are dispensable for the ancestral hematopoietic lineages. Taken together, this E-protein dependence suggests that the appearance of the full E-protein repertoire was critical to reinforce the gene regulatory circuits that drove the emergence and expansion of the lineages constituting humoral immunity.
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http://dx.doi.org/10.3389/fimmu.2019.00455DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6433000PMC
September 2020

Mice deficient of super-enhancer region reveal differential control mechanism between normal and pathological growth.

Elife 2017 06 6;6. Epub 2017 Jun 6.

Division of Functional Genomics and Systems Biology, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden.

The gene desert upstream of the oncogene on chromosome 8q24 contains susceptibility loci for several major forms of human cancer. The region shows high conservation between human and mouse and contains multiple enhancers that are activated in tumor cells. However, the role of this region in normal development has not been addressed. Here we show that a 538 kb deletion of the entire upstream super-enhancer region in mice results in 50% to 80% decrease in expression in multiple tissues. The mice are viable and show no overt phenotype. However, they are resistant to tumorigenesis, and most normal cells isolated from them grow slowly in culture. These results reveal that only cells whose MYC activity is increased by serum or oncogenic driver mutations depend on the 8q24 super-enhancer region, and indicate that targeting the activity of this element is a promising strategy of cancer chemoprevention and therapy.
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http://dx.doi.org/10.7554/eLife.23382DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5461110PMC
June 2017

The role of East Asian monsoon system in shaping population divergence and dynamics of a constructive desert shrub Reaumuria soongarica.

Sci Rep 2015 Oct 29;5:15823. Epub 2015 Oct 29.

Key Laboratory of Stress Physiology and Ecology in Cold and Arid Regions, Gansu Province, Department of Ecology and Agriculture Research, Cold and Arid Regions Environmental and Engineering Research Institute, Chinese Academy of Sciences, Lanzhou 730000, Gansu, China.

Both of the uplift of Qinghai-Tibet Plateau (QTP) and the development of East Asian monsoon system (EAMS) could have comprehensively impacted the formation and evolution of Arid Central Asia (ACA). To understand how desert plants endemic to ACA responded to these two factors, we profiled the historical population dynamics and distribution range shift of a constructive desert shrub Reaumuria soongarica (Tamaricaceae) based on species wide investigation of sequence variation of chloroplast DNA and nuclear ribosomal ITS. Phylogenetic analysis uncovered a deep divergence occurring at ca. 2.96 Mya between the western and eastern lineages of R. soongarica, and ecological niche modeling analysis strongly supported that the monsoonal climate could have fragmented its habitats in both glacial and interglacial periods and impelled its intraspecific divergence. Additionally, the population from the east monsoonal zone expanded rapidly, suggesting that the local monsoonal climate significantly impacted its population dynamics. The isolation by distance tests supported strong maternal gene flow along the direction of the East Asian winter monsoon, whose intensification induced the genetic admixture along the latitudinal populations of R. soongarica. Our results presented a new case that the development of EAMS had prominently impacted the intraspecific divergence and population dynamics of this desert plant.
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http://dx.doi.org/10.1038/srep15823DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4625182PMC
October 2015

Eight nucleotide substitutions inhibit splicing to HPV-16 3'-splice site SA3358 and reduce the efficiency by which HPV-16 increases the life span of primary human keratinocytes.

PLoS One 2013 9;8(9):e72776. Epub 2013 Sep 9.

Department of Laboratory Medicine, Lund University, Lund, Sweden.

The most commonly used 3'-splice site on the human papillomavirus type 16 (HPV-16) genome named SA3358 is used to produce HPV-16 early mRNAs encoding E4, E5, E6 and E7, and late mRNAs encoding L1 and L2. We have previously shown that SA3358 is suboptimal and is totally dependent on a downstream splicing enhancer containingmultiple potential ASF/SF2 binding sites. Here weshow that only one of the predicted ASF/SF2 sites accounts for the majority of the enhancer activity. We demonstrate that single nucleotide substitutions in this predicted ASF/SF2 site impair enhancer function and that this correlates with less efficient binding to ASF/SF2 in vitro. We provide evidence that HPV-16 mRNAs that arespliced to SA3358 interact with ASF/SF2 in living cells. In addition,mutational inactivation of the ASF/SF2 site weakened the enhancer at SA3358 in episomal forms of the HPV-16 genome, indicating that the enhancer is active in the context of the full HPV-16 genome.This resulted in induction of HPV-16 late gene expression as a result of competition from late splice site SA5639. Furthermore, inactivation of the ASF/SF2 site of the SA3358 splicing enhancer reduced the ability of E6- and E7-encoding HPV-16 plasmids to increase the life span of primary keratinocytes in vitro, demonstrating arequirement for an intact splicing enhancer of SA3358 forefficient production of the E6 and E7 mRNAs. These results link the strength of the HPV-16 SA3358 splicing enhancer to expression of E6 and E7 and to the pathogenic properties of HPV-16.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0072776PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3767658PMC
June 2014

Suppression of HPV-16 late L1 5'-splice site SD3632 by binding of hnRNP D proteins and hnRNP A2/B1 to upstream AUAGUA RNA motifs.

Nucleic Acids Res 2013 Dec 5;41(22):10488-508. Epub 2013 Sep 5.

Department of Laboratory Medicine, Section of Medical Microbiology, Lund University, 221 84 Lund, Sweden.

Human papillomavirus type 16 (HPV-16) 5'-splice site SD3632 is used exclusively to produce late L1 mRNAs. We identified a 34-nt splicing inhibitory element located immediately upstream of HPV-16 late 5'-splice site SD3632. Two AUAGUA motifs located in these 34 nt inhibited SD3632. Two nucleotide substitutions in each of the HPV-16 specific AUAGUA motifs alleviated splicing inhibition and induced late L1 mRNA production from episomal forms of the HPV-16 genome in primary human keratinocytes. The AUAGUA motifs bind specifically not only to the heterogeneous nuclear RNP (hnRNP) D family of RNA-binding proteins including hnRNP D/AUF, hnRNP DL and hnRNP AB but also to hnRNP A2/B1. Knock-down of these proteins induced HPV-16 late L1 mRNA expression, and overexpression of hnRNP A2/B1, hnRNP AB, hnRNP DL and the two hnRNP D isoforms hnRNP D37 and hnRNP D40 further suppressed L1 mRNA expression. This inhibition may allow HPV-16 to hide from the immune system and establish long-term persistent infections with enhanced risk at progressing to cancer. There is an inverse correlation between expression of hnRNP D proteins and hnRNP A2/B1 and HPV-16 L1 production in the cervical epithelium, as well as in cervical cancer, supporting the conclusion that hnRNP D proteins and A2/B1 inhibit HPV-16 L1 mRNA production.
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http://dx.doi.org/10.1093/nar/gkt803DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3905901PMC
December 2013

HPV-16 E2 contributes to induction of HPV-16 late gene expression by inhibiting early polyadenylation.

EMBO J 2012 May 22;31(14):3212-27. Epub 2012 May 22.

Section of Medical Microbiology, Department of Laboratory Medicine, Lund University, Lund, Sweden.

We provide evidence that the human papillomavirus (HPV) E2 protein regulates HPV late gene expression. High levels of E2 caused a read-through at the early polyadenylation signal pAE into the late region of the HPV genome, thereby inducing expression of L1 and L2 mRNAs. This is a conserved property of E2 of both mucosal and cutaneous HPV types. Induction could be reversed by high levels of HPV-16 E1 protein, or by the polyadenylation factor CPSF30. HPV-16 E2 inhibited polyadenylation in vitro by preventing the assembly of the CPSF complex. Both the N-terminal and hinge domains of E2 were required for induction of HPV late gene expression in transfected cells as well as for inhibition of polyadenylation in vitro. Finally, overexpression of HPV-16 E2 induced late gene expression from a full-length genomic clone of HPV-16. We speculate that the accumulation of high levels of E2 during the viral life cycle, not only turns off the expression of the pro-mitotic viral E6 and E7 genes, but also induces the expression of the late HPV genes L1 and L2.
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http://dx.doi.org/10.1038/emboj.2012.147DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3400011PMC
May 2012

Serine/arginine-rich protein 30c activates human papillomavirus type 16 L1 mRNA expression via a bimodal mechanism.

J Gen Virol 2011 Oct 22;92(Pt 10):2411-2421. Epub 2011 Jun 22.

Dublin Institute of Technology, Kevin Street, Dublin 8, Ireland.

Two splice sites on the human papillomavirus type 16 (HPV-16) genome are used exclusively by the late capsid protein L1 mRNAs: SD3632 and SA5639. These splice sites are suppressed in mitotic cells. This study showed that serine/arginine-rich protein 30c (SRp30c), also named SFRS9, activated both SD3632 and SA5639 and induced production of L1 mRNA. Activation of HPV-16 L1 mRNA splicing by SRp30c required an intact arginine/serine-repeat (RS) domain of SRp30c. In addition to this effect, SRp30c could enhance L1 mRNA production indirectly by inhibiting the early 3'-splice site SA3358, which competed with the late 3'-splice site SA5639. SRp30c bound directly to sequences downstream of SA3358, suggesting that SRp30c inhibited the enhancer at SA3358 and caused a redirection of splicing to the late 3'-splice site SA5639. This inhibitory effect of SRp30c was independent of its RS domain. These results suggest that SRp30c can activate HPV-16 L1 mRNA expression via a bimodal mechanism: directly by stimulating splicing to late splice sites and indirectly by inhibiting competing early splice sites.
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http://dx.doi.org/10.1099/vir.0.033183-0DOI Listing
October 2011