人类新基因ZNF418的研究初报

根据计算机克隆的ZNF418基因序列设计引物,从人类胚胎心脏文库中克隆了一个人类新KRAB/C2H2型锌指基因,经国际基因命名委员会批准命名为ZNF418。该基因位于染色体19 q13.43,编码蛋白由676个氨基酸残基组成的、含有1个KRAB框和17个连续排列的C2H2型锌指的蛋白质。Northern杂交的结果表明该基因在多种成人组织中表达;亚细胞定位研究证明ZNF418蛋白主要分布在胞核中。这些结果提示该基因编码一种潜在的转录因子。     

胚胎发育早期头部特异表达的小鼠新基因BSG5的克隆及功能

BrainSpecificGene 5 (BSG5 )基因是用消减差异筛选的方法克隆到的在小鼠胚胎头部特异表达的新基因。它与人的KIAA0 6 2 8基因在氨基酸水平上有 81 9%的同源性。BSG5基因长 2 4 87bp ,定位在小鼠的第 1 5号染色体上 ,包含 2个外显子。它编码的蛋白质全长 4 99个氨基酸 ,含 1 2个C2H2型的锌指结构域。以BSG5基因全长编码区为探针的原位杂交结果显示BSG5基因在小鼠胚胎发育早期头部特异表达 ,在小鼠胚胎发育稍后时期的尾部和肢芽也有表达。此外 ,以鸡胚为模型研究BSG5基因也发现该基因在鸡胚的头部特异表达。这提示BSG5基因与头部发育有密切关系 ,其结构与表达特征预示着它编码的是一个具DNA结合功能的转录调控因子     

水稻TFⅢA型锌指蛋白基因ZFP207的克隆和表达分析

锌指蛋白是一类重要的转录因子, 广泛参与植物的生长发育和胁迫应答过程。文章使用生物信息学方法从水稻中预测并克隆了一个TFⅢA型锌指蛋白基因ZFP207(GenBank 登陆号: AK063147.1), 该基因包含一个567 bp的开放阅读框, 编码一条188个氨基酸组成的多肽,其编码产物的预测分子量为20.72 kDa, 等电点为9.67。锌指蛋白ZFP207含有一个典型的TFⅢA型锌指结构, 并且在C端含有一个可能具有转录抑制功能的EAR-motif, 但不具有任何已知的核定位信号。系统发生分析结果表明, ZFP207与植物中已经发现的单锌指蛋白亲缘关系较近。通过RT-PCR方法分析了ZFP207基因在成株期水稻不同组织中的表达, 发现ZFP207在茎和叶中表达量较高, 而在穗和根中表达量较低。在酵母中的转录激活实验结果显示, ZFP207在酵母中不具有转录激活功能。     

包含BTB锌指结构的新基因Bsg2结构特性及其在发育阶段的组织表达特异性

通过消减差异筛选法寻找小鼠胚胎发育过程中在脑中特异表达的基因 .克隆得到的脑特异表达新基因 2 (brainspecificgene 2 ,简称Bsg2 )长 36 91bp ,通过生物信息学方法预测其编码一个含713个氨基酸的锌指蛋白 .此蛋白N端有一个BTB(BR C ,ttkandbab)结构域 ,C端有 9个连续的C2H2锌指结构 .该基因定位在小鼠 12号染色体上 ,包含 1个内含子和 2个外显子 .应用生物信息学和RT PCR方法分别检验该基因在小鼠各组织中的表达 .结果表明 ,Bsg2基因在小鼠胚胎及成体的各组织中普遍表达 ,在脾、肾、睾丸、肠、子宫和脑的表达水平较强 .利用整体 (wholemount)原位杂交研究其时空表达模式 .结果显示 ,Bsg2在早期的小鼠胚胎和不同时期鸡胚的头部均特异表达 ,在11d鼠胚的肢芽里也有较强的表达 .Bsg2基因的结构和表达特征预示它编码 1个具有DNA结合功能的转录调控因子 ,同时揭示它在脑的发育和器官形成过程中发挥着重要作用     

KRAB型锌指蛋白(KZNF)的研究进展

KRAB型锌指蛋白是哺乳动物中最大的转录调控因子家族, 它的多数成员在基因组上成簇分布。其结构特征是N端含有KRAB结构域, C端含有多个C2H2型锌指结构。KRAB结构域为一蛋白质-蛋白质相互作用区, 可以与多种协同转录抑制因子和转录因子结合, 使KRAB型锌指蛋白作为转录因子和/或转录调控因子发挥依赖于DNA结合的转录抑制功能, 在胚胎发育、细胞分化、细胞转化及细胞周期的调控中发挥重要功能。     

胡杨锌指蛋白基因克隆及其结构分析

锌指蛋白属于核转录因子家族,在原核生物与真核生物基因转录调控中发挥作用。分析了耐盐锌指蛋白Alfin-1基因在苜蓿与拟南芥中的保守性后,设计了一对引物。以胡杨水培叶片为材料,从总RNA中通过RT-PCR分离得到一个锌指蛋白基因,其cDNA长924bp。分析其氨基酸序列表明,存在一个典型的Cys2/His2锌指结构,从第556位开始有一个富含G的启动子结合位点GTGGGG。由于具有相同功能的转录因子在结构和DNA结合区的氨基酸序列上具有保守性,因此,从结构分析上可以推测该基因与Alfin-1在功能上是有一定的相关性。     

水稻多逆境诱导基因OsMsr4的克隆与表达分析

为深入了解水稻逆境反应的分子机理和发现新的耐逆相关功能基因,采用Affymetrix水稻表达芯片分析超级稻两优培九母本培矮64S(Oryza sativa L.)不同生长发育时期、不同组织器官全基因组在低温、干旱、高温逆境胁迫下的表达水平,筛选出多个多因子诱导高表达特异基因(待另文发表).OsMsr4是其中一个在多种逆境条件,各生长发育时期与组织器官,其表达量均显著上调的基因,用实时定量PCR方法对其表达水平进行了进一步的分析,所得结果与基因芯片结果基本吻合.用 PCR方法扩增获得长为550 bp全长基因序列,其编码的144个氨基酸残基形成Cys2His2型双锌指结构蛋白,并且锌指结构的α-螺旋区含有植物锌指蛋白特定的保守序列QALGGH.因此,OsMsr4有可能是TFⅢA型锌指蛋白,作为转录因子参与各种环境胁迫应答反应,调控多个逆境相关基因表达.     

人类锌指结构新基因ZNF18的克隆和表达谱分析

在很多转录因子中发现的锌指结构,被认为在人类心脏的发育和相关疾病的发生过程中发挥重要的作用。本文报道了克隆和表达分析人类新的锌指蛋白基因ZNF18。该基因cDNA长2 767 bp,编码一个有549个氨基酸的蛋白,这一蛋白含有一个SCAN结构域,一个KRAB结构域和5个连续的C2H2型锌指结构域。ZNF18蛋白与小鼠Zfp535有77％的同源性。ZNF18基因定位于人染色体17p12~p13,包含9个外显子和8个内含子。以ZNF18全长编码区为探针进行Northern杂交,结果显示ZNF18在成体小鼠各组织中广泛表达,但在心脏中低丰度表达。整体原位杂交结果显示,ZNF18基因在小鼠胚胎的表达有很高的动态性。ZNF18主要在E7.5小鼠胚胎的胚外组织表达,E8.5出现了胚胎躯干前端表达。ZNF18从E9.0开始在胚胎的心脏和尾部表达,尤其在E10.5胚胎的心脏高丰度表达。这提示ZNF18基因与心脏发育过程可能有密切的关系。     

一个可能与T细胞发育相关的新的C2H2型锌指蛋白基因的克隆(英)

一些在组织和细胞分化中起重要作用的蛋白质包含锌指结构域.为了克隆分离和研究与造血细胞分化和发育成熟相关的蛋白基因,利用编码C2H2型锌指蛋白结构域中部分保守氨基酸序列设计简并引物,以骨髓cDNA为模板,进行PCR扩增,得到若干新的锌指蛋白基因EST.用其中一条为探针筛选人骨髓cDNA文库,获得了一个新的锌指蛋白基因全长cDNA,GenBank收录号为AF246126,长3 888 bp,包括一个完整阅读框,编码686个氨基酸,包括17个典型的和2个非典型的C2H2模体,命名为HZF2. RNA印迹、人多组织mRNA斑点杂交分析结果显示, 其在T淋巴细胞发育和定居的器官组织胸腺、淋巴结中有较高表达,在脾脏、胎肝有中度表达,在B淋巴细胞发育的骨髓中表达很低,在外周血几个淋巴细胞系中仅有极微量的表达,提示HZF2可能对于T淋巴细胞发育和增殖有重要功能.该基因也在脑组织的若干部位、胎盘及肾上腺有较高表达,在多种其他组织细胞有微量表达,说明其可能对维持这些组织细胞的生理功能也起一定作用.将编码HZF2读框的DNA顺序克隆到pEGFP-N1载体中,转染3T3细胞,证明表达的HZF2-GFP融合蛋白定位于细胞核,这与根据HZF2蛋白结构推测其可能作为DNA结合蛋白行使调节基因转录的功能是一致的.     

陆地棉SUPERMAN类似锌指蛋白基因的克隆与表达分析

锌指蛋白是生物体内数量最多的转录调控因子,它在动植物的生长发育中都起到十分重要的作用。SUPERMAN类锌指蛋白只含有1个锌指结构。我们根据这类蛋白的保守结构域设计简并引物,通过RT-PCR从棉花中获得了3个这个家族成员的EST,得到1个锌指蛋白基因的全长序列,该基因的编码区长744 bp,编码长248个氨基酸的多肽,其氨基酸序列与GenBank中登录的一个拟南芥RBE蛋白有40%的同源性。此基因被命名为GZFP。它含有保守的锌指结构并在多肽链的C-端具有富含亮氨酸的保守结构域,GZFP含有核定位信号并且没有内含子。GZFP基因在棉花花蕾、子房、花瓣和根中的表达量要高于木质部、韧皮部、叶片、纤维和种子。GZFP基因的表达量很低,在GenBank中没有任何和它同源的EST序列存在。对GZFP 5′侧翼区进行分析发现有数个花粉和根特异表达相关元件,4个与Dof蛋白作用的核心序列,4个与光诱导相关的元件。      

A Unique Protease Cleavage Site Predicted in the Spike Protein of the Novel Pneumonia Coronavirus (2019-nCoV) Potentially Related to Viral Transmissibility

正Dear Editor,In December 2019, a novel human coronavirus caused an epidemic of severe pneumonia(Coronavirus Disease 2019,COVID-19) in Wuhan, Hubei, China(Wu et al. 2020; Zhu et al. 2020). So far, this virus has spread to all areas of China and even to other countries. The epidemic has caused 67,102 confirmed infections with 1526 fatal cases     

Curcuminoids as inhibitors of thioredoxin reductase: A receptor based pharmacophore study with distance mapping of the active site

Curcumin is the yellow pigment of turmeric that interacts irreversibly forming an adduct with thioredoxin reductase (TrxR), an enzyme responsible for redox control of cell and defence against oxidative stress. Docking at both the active sites of TrxR was performed to compare the potency of three naturally occurring curcuminoids, namely curcumin, demethoxy curcumin and bis-demethoxy curcumin. Results show that active sites of TrxR occur at the junction of E and F chains. Volume and area of both cavities is predicted. It has been concluded by distance mapping of the most active conformations that Se atom of catalytic residue SeCYS498, is at a distance of 3.56 from C13 of demethoxy curcumin at the E chain active site, whereas C13 carbon atom forms adduct with Se atom of SeCys 498. We report that at least one methoxy group in curcuminoids is necessary for interation with catalytic residues of thioredoxin. Pharmacophore of both active sites of the TrxR receptor for curcumin and demethoxy curcumin molecules has been drawn and proposed for design and synthesis of most probable potent antiproliferative synthetic drugs.     

Comparative morphology of the carpel in the Liliaceae: Hewardieae, Petrosavieae, and Tricyrteae

The young pistils in the melanthioid tribes, Hewardieae, Petrosavieae and Tricyrteae, are uniformly tricarpellate and syncarpous. They lack raphide idioblasts. All are multiovulate, with bitegmic ovules. The Petrosavieae are marked by the presence of septal glands and incomplete syncarpy. Tepals and stamens adhere to the ovary in the Hewardieae and the Petrosavieae but not in the Tricyrteae. Two vascular bundles occur in the stamens of the Hewartlieae and Tricyrtis latifolia. Ventral bundles in the upper part of the ovary of the Hewardieae are continuous with compound septal bundles and placental bundles in the lower part. Putative ventral bundles occur in the alternate position in the Tricyrteae and putative placental bundles in the opposite. position in the Petrosavieae. The dichtomously branched stigma in each carpel of the Tricyrteae is supplied by a bifurcated dorsal bundle.     

Enterovirus 71 3C proteolytically processes the histone H3 N-terminal tail during infection

Highlights
1. The N-terminal tail of histone H3 is specifically cleaved during EV71 infection.
2. Viral protease 3C is identified as a protease responsible for proteolytically processing the N-terminal H3 tail.
3. Our finding reveals a new epigenetic regulatory mechanism for Enterovirus 71 in virus-host interactions.     

Detection of EBV and HHV6 in the Brain Tissue of Patients with Rasmussen’s Encephalitis

Rasmussen’s encephalitis (RE) is a rare pediatric neurological disorder, and the exact etiology is not clear. Viral infection may be involved in the pathogenesis of RE, but conflicting results have reported. In this study, we evaluated the expression of both Epstein-Barr virus (EBV) and human herpes virus (HHV) 6 antigens in brain sections from 30 patients with RE and 16 control individuals by immunohistochemistry. In the RE group, EBV and HHV6 antigens were detected in 56.7% (17/30) and 50% (15/30) of individuals, respectively. In contrast, no detectable EBV and HHV6 antigen expression was found in brain tissues of the control group. The co-expression of EBV and HHV6 was detected in 20.0% (6/30) of individuals. In particular, a 4-year-old boy had a typical clinical course, including a medical history of viral encephalitis, intractable epilepsy, and hemispheric atrophy. The co-expression of EBV and HHV6 was detected in neurons and astrocytes in the brain tissue, accompanied by a high frequency of CD8⁺ T cells. Our results suggest that EBV and HHV6 infection and the activation of CD8⁺ T cells are involved in the pathogenesis of RE.     

Perinatal Vertical Transmission of Chikungunya Virus in Ruili,a Town on the Border between China and Myanmar

正Dear Editor,Chikungunya virus (CHIKV), an arbovirus in the family of Togaviridae, genus Alphavirus, is transmitted by the A.aegyptii or A. albopictus mosquito, and causes disease in humans characterized by fever, rash, and arthralgia (Silva and Dermody 2017; Suhrbier 2019). It was first reported in 1953 in Tanzania, and caused only a few outbreaks and sporadic cases in Africa and Asia in last century. However, in the epidemic in 2004, CHIKV acquired mutations that conferred enhanced transmission by the A. albopictus mosquito(Schuffenecker et al. 2006). Since then, it has successively caused outbreaks in Africa, the Indian Ocean, South East Asia, the South America, and Europe (Zeller et al. 2016).     

Development of a Novel Reverse Transcription Loop-Mediated Isothermal Amplification Method for Rapid Detection of SARS-CoV-2

In conclusion, the novel visual RT-LAMP assay is a simple, rapid, and sensitive approach for detection of SARS-CoV-2, and it is ready for application in primary care and community hospitals or health care centers, and even patients' own houses in response to the current SARS-CoV-2 epidemic because the assay does not require sophisticated equipment and skilled personnel. Furthermore, it is also ready to be used in fields for screening samples from wild animals and environments to facilitate the identification of potential intermediate hosts that mediate the cross-species transmission of SARS-CoV-2 from bats to humans.