应用CRISPR/Cas9系统构建Rev-erbβ基因敲除的HEK293细胞系

目的利用成簇的、规律间隔的短回文重复序列/Cas9核酸酶(CRISPR/Cas9)基因组编辑技术,构建Rev-erbβ基因敲除的HEK293细胞系。方法通过单向导RNA(sgRNA)介导Cas9蛋白对目的基因靶位点DNA进行特异性的切割,然后经DNA同源重组单向导RNA或非同源末端连接方式进行修复,以实现对Rev-erbβ基因进行敲入、敲除修饰操作的目的。首先,针对Rev-erbβ基因设计4个sgRNA,经筛选选择活性较高的sgRNA1及sgRNA2用于构建p CMV-h Cas9-U6-Rev-erbβsgRNA1sgRNA2串联载体。然后将p CMV-h Cas9-U6-Rev-erbβsgRNA1sgRNA2和p Ad-E1/hRev-erbβdonor质粒载体共转染至HEK293细胞,通过药物筛选、克隆化及序列测序获得整合有外源供体基因片段的一条链,另一条链为片段缺失的Rev-erbβ基因完全敲除的HEK293(Rev-erbβ-/-)细胞系。最后通过用Western blot法和实时定量PCR对敲除Rev-erbβHEK293细胞系(C3-6)进行检测。结果敲除Rev-erbβ基因的HEK293细胞系中均未检测到Rev-erbβmRNA和蛋白质的表达。结论利用CRISPR/Cas9技术,成功构建了基因定点修饰和敲除的Rev-erbβ-/-HEK293细胞系,为Rev-erbβ的功能和作用机制研究提供有效工具。     

核仁磷酸蛋白基因NPM1敲除人宫颈癌细胞株的构建及功能

目的通过CRISPR/Cas9系统定向敲除人类宫颈癌细胞(HELA)的核仁磷酸蛋白1基因(nucleophosmin1, NPM1),探讨敲除对HELA细胞生物学行为的影响。方法利用http://crispr.mit.edu sgRNA在线设计工具设计sgRNA,通过T7E1系统筛选合适的sgRNA,将设计好的质粒通过转染的方式转入HELA细胞株,通过博来霉素(zeocin)抗生素进行筛选,通过Western blot,PCR,基因测序等手段确认敲除细胞系的建立,通过免疫荧光的方式观察敲除细胞株。结果 T7E1酶切PCR退火产物之后琼脂糖凝胶结果表明,CRISPR/Cas9系统对HELA细胞基因组进行了切割,并在同源重组时发生了碱基错配;Western blot结果说明基因敲除后NPM1蛋白表达消失;基因测序的结果表明敲除细胞系建立的成功;免疫荧光的结果表明该细胞系出现异常核仁现象。结论 NPM1敲除后细胞核仁异常,可能影响细胞正常生命进程。     

CRISPR/Cas9技术敲除RAW264.7细胞的GPR43基因抑制其对肺炎克雷伯菌的吞噬功能

目的利用成簇的规律间隔的短回文重复序列/Cas9核酸酶(CRISPR/Cas9)技术构建稳定敲除G蛋白偶联受体43(GPR43)基因的RAW264.7细胞系,探究GPR43基因在肺炎克雷伯菌感染过程中的作用机制。方法设计3对针对GPR43基因的小导向RNA(sgRNA),将sgRNA插入pLenticrisprV2质粒中,利用慢病毒包装系统包装含有sgRNA的重组质粒pLenticrisprV2;将病毒感染RAW264.7细胞,嘌呤霉素筛选单克隆细胞;将扩增的单克隆细胞提取基因组DNA,测序GPR43基因相关序列并与野生型GPR43基因进行比对,确认敲除成功的细胞株(GPR43~(-/-) RAW264.7细胞), Western blot法检测GPR43蛋白水平。肺炎克雷伯菌感染GPR43~(-/-) RAW264.7细胞,实时定量PCR法检测细菌感染后细胞内白细胞介素1β(IL-1β)、 IL-6和肿瘤坏死因子α(TNF-α)表达水平的变化,并观察敲除GPR43后, RAW264.7细胞吞噬能力的变化。结果挑选的单克隆细胞经Western blot验证GPR43蛋白不表达,并且DNA测序结果显示在sgRNA插入位置缺失34个碱基,证明成功敲除GPR43基因。GPR43~(-/-) RAW264.7细胞感染肺炎克雷伯菌后,细胞中的IL-1β、 IL-6和TNF-α表达水平均低于对照组,且GPR43~(-/-) RAW264.7细胞对肺炎克雷伯菌的吞噬能力降低。结论 CRISPR/Cas9技术敲除GPR43基因,抑制其对肺炎克雷伯菌的吞噬功能及炎性细胞因子的产生。     

CRISPR/Cas9介导下高效敲除SQSTM1/p62基因的Hela细胞模型的建立

目的 :探讨针对p62双sgRNA向导CRISPR/Cas9基因编辑效率。方法 :采用CRISPR/Cas9基因编辑技术成功敲除p62基因,通过细胞有限稀释法和嘌呤霉素筛选,免疫印迹法验证双sgRNA和单sgRNA向导的基因编辑成功率;流式细胞仪验证p62缺失对Hela细胞凋亡的影响。结果 :免疫印迹分析得出双sgRNA导向的p62敲除效率高于单sgRNA导向的敲除,靶序列测序比对分析确认p62编码基因发生大片段缺失突变。H_2O_2处理稳定敲除的Hela细胞系显示,p62基因敲除能明显抑制Hela细胞H_2O_2诱导的早期细胞凋亡。结论 :成功建立了p62敲除的Hela细胞系,双sgRNA向导的CRISPR/Cas9基因编辑体系可能是一种更有效的编辑工具。     

基于CRISPR/Cas9系统的HEK293T细胞DMD基因第51号外显子的靶向敲除

目的应用CRISPR/Cas9基因编辑技术,完成HEK293T细胞中DMD基因第51号外显子(exon51)高效的靶向敲除。方法设计靶向人DMD基因exon51 5'端及3'端的sgRNA并克隆至CRISPR/Cas9载体质粒PX459中,转染至HEK293T细胞后,提取基因组DNA并使用Surveyor法检测切割活性;使用目标外显子两端切割活性最高的sgRNA构建PX459-2sgRNA质粒,转染至HEK293T细胞后用PCR及T载体测序检测靶向外显子切除情况。结果50%的HEK293T细胞中DMD基因exon51被定向切除,编辑效率较高。结论建立使用CRISPR/Cas9单质粒敲除人DMD基因exon51的平台,为DMD及其他遗传病的基因治疗研究奠定实验基础。     

利用CRISPR/Cas9技术构建DOC-1R基因敲除的HEK-293稳转细胞系

目的利用CRISPR/Cas9技术敲除人胚肾(human embryonic kidney cell,HEK-293)细胞中DOC-1R,构建DOC-1R敲除的HEK-293稳转细胞系,用于进一步讨论DOC-1R的生物学功能。方法根据CRISPR/Cas9设计原则,设计向导RNA(single-guide RNA,sgRNA),构建表达载体,对sgRNA测序并转染包装HEK-293T收集上清液测定病毒滴度。前期用Cas9-puro慢病毒感染HEK-293,用已制备的DOC-1R慢病毒感染稳转Cas9的HEK-293,72 h后显微镜下观察HEK-293表达红色荧光蛋白,并用Western blot检测HEK-293中DOC-1R的表达以确定沉默效果。结果测序显示插入的sgRNA序列正确,表达载体成功构建,显微镜下观察到,90%以上HEK-293表达红色荧光蛋白,HEK-293中DOC-1R蛋白表达减少,确定了DOC-1R敲除效果最明显的序列为GCCTACCTATGCTGGCAGCA。结论利用CRISPR/Cas9技术成功构建DOC-1R基因敲除的细胞系,为进一步研究该基因的功能奠定了基础。     

利用CRISPR/Cas9系统构建4T1细胞CXCR4基因敲除稳定细胞株

目的 利用CRISPR/Cas9系统敲除4T1细胞中的CXCR4基因,构建稳定敲除CXCR4基因的4T1细胞株。 方法 根据CRISPR/Cas9靶点设计原则,在美国国立生物技术信息中心（NCBI）上找到CXCR4基因序列的外显子区域,设计两条sgRNA,用LentiCRISPRv2作为载体构建LentiCRISPRv2-sgRNA重组质粒并转化至感受态的Stbl3菌体中,挑取单克隆测序验证并扩大培养提质粒后转染至293T细胞中包装成慢病毒。 收集病毒并感染4T1细胞,通过嘌呤霉素筛选并用有限稀释法分离培养出单克隆细胞。 提取筛选出的单克隆细胞基因组DNA并对敲除位点附近的DNA片段进行PCR扩增并测序;用Real-time PCR检测细胞株CXCR4基因mRNA表达情况;用免疫印迹法检测CXCR4蛋白质的表达情况。 结果 LentiCRISPRv2-sgRNA重组质粒构建成功;经过基因组DNA片段PCR扩增测序得1株缺失27 bp的稳定敲除CXCR4基因的细胞株;细胞株CXCR4mRNA的表达量低且几乎无CXCR4蛋白质的表达。 结论 通过CRISPR/Cas9系统获得靶向敲除CXCR4基因的重组质粒,并筛选出稳定敲除CXCR4基因的细胞株。     

腺相关病毒介导的体内睾丸组织基因特异性敲除系统的建立

目的建立一套可用于体内睾丸组织特异性敲除基因的系统。方法利用同源重组技术将CRISPR/Cas9系统中sgRNA功能元件插入到AAV表达载体,将人源Wee1 2#sgRNA构建入改造的AAV-sgRNA(新版)载体中进行病毒包装,并感染稳定表达Cas9的HeLa-spCas9细胞验证该载体的基因敲除效率。筛选睾丸组织特异表达基因Sycp3的sgRNA靶点,构建入AAV-sgRNA(新版)载体中,进行病毒包装,利用显微注射技术将病毒注射入小鼠睾丸组织曲细精管内,通过T7E1分析体内细胞的基因敲除效果。结果构建成功的AAV-sgRNA载体能够进行病毒包装并在体外细胞水平上对人源Wee1进行基因编辑,与慢病毒介导的CRISPR/Cas9系统中的载体编辑效率相比无明显差异。同时,该系统能在体内水平对Sycp3进行基因编辑。结论成功建立一套可用于在体内睾丸组织中进行特异性敲除目标基因的系统,为生殖体内功能研究提供一个新的思路和方法。     

应用CRISPR/Cas9系统构建敲除APE1基因的AC16心肌细胞株

目的应用CRISPR/Cas9系统构建敲除APE1基因的AC16心肌细胞株,为研究APE1在心肌细胞的功能提供研究基础。方法根据RISPR/Cas9靶向原理设计人APE1基因的导向RNA(sgRNA),构建sgRNA-LentiCRISPRV2重组质粒并转入293T细胞制备sgRNA-Cas9慢病毒;该病毒浸染AC16心肌细胞,嘌呤霉素筛选出阳性细胞并稀释至单克隆。免疫印迹法测定单克隆细胞中APE1蛋白表达。结果免疫印迹法检测的结果显示,筛选出的单克隆细胞的APE1蛋白表达完全缺失;PCR产物测序结果表明,靶向敲除APE1的心肌细胞,不存在sgRNA介导CRISPR-Cas9随机的核苷酸插入。结论应用CRISPR/Cas9系统成功构建了敲除APE1基因的AC16心肌细胞株。     

规律间隔成簇短回文重复序列/相关蛋白9靶向Rho GDIα基因敲除质粒的构建及其对小鼠肝癌细胞系Hepa 1-6迁移的影响

目的利用规律间隔成簇短回文重复序列/相关蛋白9(CRISPR/Cas9)技术构建Rho鸟苷酸解离抑制因子α(GDIα)的基因敲除载体,并探讨干扰Rho GDIα后对小鼠肝癌细胞Hepa 1-6迁移的影响。方法根据CRISPR/Cas9靶点设计原则,设计Rho GDIα的向导RNA(sgRNA)序列,并与PX458载体相连,构建Rho GDIα基因敲除重组质粒PX458-Rho GDIα-sgRNA1和PX458-Rho GDIα-sgRNA2;脂质体转染法将重组质粒转染入Hepa 1-6细胞抑制Rho GDIα的基因表达;RT-PCR法检测Rho GDIα被抑制后的mRNA表达情况;划痕法检测Rho GDIα干扰后Hepa 1-6细胞迁移距离的差异;迁移小室法检测抑制Rho GDIα后Hepa 1-6细胞迁移数量的差异。结果成功构建了Rho GDIα的CRISPR/Cas9基因敲除质粒PX458-Rho GDIα-sgRNAs;转染有PX458-Rho GDIα-sgRNA1的Hepa 1-6细胞与对照组只转染空载体PX458的细胞相比,Rho GDIα的表达被明显抑制(P<0.05),而且该组细胞从划痕起始处迁移到空白处距离较远,从迁移小室上端迁移到底端数目明显增多,差异极其显著(P<0.01),说明Rho GDIα被抑制后肝癌细胞的迁移能力提高。结论CRISPR/Cas9法构建的重组质粒PX458-Rho GDIα-sgRNA1可以有效抑制Rho GDIα的基因表达;Rho GDIα被抑制后明显促进小鼠肝癌细胞Hepa 1-6的迁移,提示在体情况下,Rho GDIα的表达可能起到抑制细胞迁移的重要作用,在肿瘤组织中,可以利用过表达Rho GDIα来抑制肿瘤细胞的转移。     

Subgenomic RNA as a riboregulator: negative regulation of RNA replication by Barley yellow dwarf virus subgenomic RNA 2

Barley yellow dwarf virus (BYDV) generates three 3'-coterminal subgenomic RNAs (sgRNAs) in infected cells. Translation of BYDV genomic RNA (gRNA) and sgRNA1 is mediated by the BYDV cap-independent translation element (BTE) in the 3' untranslated region. sgRNAs 2 and 3 are unlikely to be mRNAs. We proposed that accumulation of sgRNA2, which contains the BTE in its 5' UTR, regulates BYDV replication by trans-inhibiting translation of the viral polymerase from genomic RNA (gRNA). Here, we tested this hypothesis and found that: (i) co-inoculation of the BTE or sgRNA2 with BYDV RNA inhibits BYDV RNA accumulation in protoplasts; (ii) Brome mosaic virus (BMV), engineered to contain the BTE, trans-inhibits BYDV replication; and (iii) sgRNA2 generated during BYDV infection trans-inhibits both GFP expression from BMV RNA and translation of a non-viral reporter mRNA. We conclude that sgRNA2, via its BTE, functions as a riboregulator to inhibit translation of gRNA. This may make gRNA available as a replicase template and for encapsidation. Thus, BYDV sgRNA2 joins a growing list of trans-acting regulatory RNAs.     

Two classes of subgenomic RNA of grapevine virus A produced by internal controller elements

Grapevine virus A (GVA), a species of the recently established genus Vitivirus, consists of an approximately 7.3-kb single-stranded RNA genome of positive polarity, organized into five open reading frames (ORFs). The virus, which is closely associated with the grapevine rugose wood disease complex, has been poorly investigated genetically. We explored the production of viral RNAs in a GVA-infected Nicotiana benthamiana herbaceous host and characterized one nested set of three 5'-terminal sgRNAs of 5.1, 5.5, and 6.0 kb, and another, of three 3'-terminal sgRNAs of 2.2, 1.8, and 1.0 kb that could serve for expression of ORFs 2-3, respectively. Neither 3'- nor 5'-terminal sgRNAs, which would correspond to ORF5, was detected, suggesting that expression of this ORF occurs via a bi- or polycistronic mRNA. The 5'-terminal sgRNAs were abundant in dsRNA-enriched extracts. Cloning and sequence analysis of the 3' end of 5.5-kb 5'-terminal sgRNA and the 5' end of the 1.8-kb 3'-terminal sgRNA suggested that a mechanism other than specific cleavage was involved in production of these sgRNAs. Apparently, the production of the 5'- and 3'-terminal sgRNAs was controlled by sequences upstream of the 5'-terminus of each of ORFs 2-4. Detection of both plus and minus strands of the 5'- and 3'-terminal sgRNAs, though in different levels of accumulation, suggested that each of these cis-acting elements is involved in production of four RNAs: a 3'-terminal plus-strand sgRNA which could act as an mRNA, the corresponding 3'-terminal minus-strand RNA, a 5'-terminal plus-strand sgRNA, and the corresponding 5'-terminal minus-strand RNA.     

p62在喉癌Hep-2细胞化疗耐药中的作用

目的:探讨p62在喉癌细胞Hep-2化疗耐药中的作用及潜在的作用机制。方法:实时荧光定量聚合酶链式反应(RT-q PCR)及Western blot法检测喉癌耐药细胞Hep-2/5-FU及其亲本细胞Hep-2中p62的表达水平。在Hep-2/5-FU细胞中转染p62 siRNA敲减p62的表达,采用CCK-8法和流式细胞术检测细胞生存率及细胞凋亡状态;检测细胞中丙二醛(malondialdehyde,MDA)的含量及超氧化物歧化酶(superoxide dismutase,SOD)、谷胱甘肽过氧化物酶(glutathione peroxidase,GSH-Px)的活性来反映细胞氧化应激水平。Western blot检测细胞凋亡相关调控因子Bcl-2、Bax、caspase-8/cleaved caspase-8、caspase-3/cleaved caspase-3的蛋白水平及抗氧化通路Keap1/Nrf2的活性。结果:耐药细胞株Hep-2/5-FU中p62的mRNA及蛋白表达水平均明显高于亲本细胞株Hep-2;并且在亲本细胞株Hep-2中,p62和Nrf2的蛋白表达水平随着顺铂的浓度增加不断升高。沉默p62可抑制喉癌耐药细胞Hep-2/5-FU的生存,促进其凋亡,上调MDA的含量,降低SOD和GSH-Px的活性,同时上调Bax、cleaved caspase-8、cleaved caspase-3和Keap1的蛋白水平,下调Bcl-2、Nrf2及HO-1的蛋白表达。结论:喉癌耐药细胞Hep-2/5-FU中沉默p62可恢复细胞对5-FU的敏感性,其机制可能与抑制Keap1/Nrf2信号通路的活化、调控细胞内氧化应激反应及细胞凋亡有关。     

Activated iNKT cells promote Vγ9Vδ2-T cell anti-tumor effector functions through the production of TNF-α

Vγ9Vδ2-T cells constitute a proinflammatory lymphocyte subpopulation with established antitumor activity. Phosphoantigens activate Vγ9Vδ2-T cells in vivo and in vitro. We studied whether the antitumor activity of Vγ9Vδ2-T cells can be potentiated by invariant NKT cells (iNKT), an important immunoregulatory T cell subset. When activated by the glycolipid α-galactosylceramide (α-GalCer), iNKT produce large amounts of cytokines involved in antitumor immune responses. Monocyte-derived dendritic cells were loaded with both phosphoantigens (using aminobisphosphonates) and α-GalCer during maturation and subsequently co-cultured with Vγ9Vδ2-T and iNKT cells. Aminobisphosphonates dose-dependently enhanced Vγ9Vδ2-T cell activation, and this was potentiated by α-GalCer-induced iNKT co-activation. iNKT co-activation also enhanced the IFN-γ production and cytolytic potential of Vγ9Vδ2-T cells against tumor cells. Using transwell experiments and neutralizing antibodies cross-talk between iNKT and Vγ9Vδ2-T cells was found to be mediated by TNF-α. Our data provide a rationale for combining both activating ligands to improve Vγ9Vδ2-T cell based approaches in cancer-immunotherapy.     

Spred1, a negative regulator of Ras�CMAPK�CERK, is enriched in CNS germinal zones, dampens NSC proliferation, and maintains ventricular zone structure

Neural stem cells (NSCs) have great potential for self-renewal, which must be tightly regulated to generate appropriate cell numbers during development and to prevent tumor formation. The Ras–MAPK–ERK pathway affects mitogen-stimulated proliferation, and negative regulators are likely to be important for keeping self-renewal in check. Sprouty-related protein with an EVH1 domain (Spred1) is a recently discovered negative Ras–MAPK–ERK regulator linked to a neurofibromatosis 1 (NF-1)-like human syndrome; however, its role in CNS development has not been explored. We show that Spred1 is highly enriched in CNS germinal zones during neurogenesis. Spred1 knockdown increases NSC self-renewal and progenitor proliferation cell-autonomously, and overexpression causes premature differentiation. Surprisingly, Spred1 knockdown in vivo in the embryonic mouse forebrain frequently resulted in periventricular heterotopia, developmental abnormalities often associated with mutations in genes in the vesicular trafficking pathway that cause disruption of germinal zones and impair cell migration. In cortical progenitor cells, Spred1 localizes within distinct vesicles, indicating a potential role in transport. Spred1 knockdown gradually leads to disruption of the apical ventricular zone and loss of radial glia alignment. This impairs late neuronal migration, resulting in the formation of periventricular masses. Thus, Spred1 is critical for normal cortical development, as it modulates progenitor self-renewal/proliferation and helps maintain the integrity and organization of germinal zones.     

Sox2 enhances the tumorigenicity and chemoresistance of cancer stem-like cells derived from gastric cancer

Gastric cancer stem-like cells(GCSCs) have been identified to possess the ability of self-renewal and tumor initi-ation.However,the mechanisms involved remain largely unknown.Here,we isolated and characterized the GCSCs by side population(SP) sorting procedure and cultured sphere cells(SC) from human gastric cancer cell lines SGC-7901,BGC-823,MGC-803,HGC-27 and MKN-28.The sorting and culture assay revealed that SP cells proliferated in an asymmetric division manner.In addition,SP cells exhibited a higher potential of spheroid colony formation and greater drug resistance than non-SP cells(NSP).Moreover,the SC were found with enhanced capabilities of drug resistance in vitro and tumorigenicity in vivo.Sox2 mRNA and protein was highly and significantly overex-pressed in the SP cells and SC.Importantly,downregulation of Sox2 with siRNA obviously reduced spheroid colony formation and doxorubicin efflux,as well as increased apoptosis rate in sphere cells in vitro and suppressed tumori-genicity in vivo.These results suggest that both SP cells and cultured SC enrich with GCSCs and that Sox2 plays a pivotal role in sustaining stem cell properties and might be a potential target for gastric cancer therapy.