Distribution analysis of TRH in Bactrocera dorsalis using a CRISPR/Cas9-mediated reporter knock-in strain

Although the study of many genes and their protein products is limited by the availability of high-quality antibodies, this problem could be solved by fusing a tag/reporter to an endogenous gene using a gene-editing approach. The type II bacterial CRISPR/Cas system has been demonstrated to be an efficient gene-targeting technology for many insects, including the oriental fruit fly Bactrocera dorsalis. However, knocking in, an important editing method of the CRISPR/Cas9 system, has lagged in its application in insects. Here, we describe a highly efficient homology-directed genome editing system for B. dorsalis that incorporates coinjection of embryos with Cas9 protein, guide RNA and a short single-stranded oligodeoxynucleotide donor. This one-step procedure generates flies carrying V5 tag (42 bp) in the BdorTRH gene. In insects, as in other invertebrates and in vertebrates, the neuronal tryptophan hydroxylase (TRH) gene encodes the rate-limiting enzyme for serotonin biosynthesis in the central nervous system. Using V5 monoclonal antibody, the distribution of TRH in B. dorsalis at different developmental stages was uncovered. Our results will facilitate the generation of insects carrying precise DNA inserts in endogenous genes and will lay foundation for the investigation of the neural mechanisms underlying the serotonin-mediated behaviour of B. dorsalis.     

CRISPR/Cas9-based functional characterization of the pigmentation gene ebony in Plutella xylostella

Body pigmentation is an important character of insects in adapting to biotic and abiotic environmental challenges. Additionally, based on the relative ease of screening, several genes involved in insect melanization have been used in classic genetic studies or as visual markers in constructing transgenic insects. Here, a homologue of the Bombyx mori melanization-inhibiting gene ebony, associated with the conversion of dopamine to N-β-alanyl dopamine, was identified in a global pest, Plutella xylostella. The CRISPR/Cas9 system was applied to generate multiple Pxebony knockout alleles which were crossed to produce a Pxebony knockout strain, showing darker pigmentation in larvae, pupae and adults, compared with wildtype. Interestingly, we observed that Pxebony heterozygotes displayed an intermediate darkened phenotype, indicating partial dominance between the knockout and wildtype alleles. The fitness costs of Pxebony deficiency were also assessed in the mutant strain, indicating that embryo hatchability and larval survival were significantly reduced, while the eclosion rate was not obviously affected. Our work provides a potential target for exploring CRISPR-based genetics-control systems in this economically important pest lepidopteran.     

利用CRISPR/Cas9技术敲除K562细胞中的SMIM1基因

目的利用慢病毒介导的CRISPR/Cas9基因编辑技术,在K562细胞系中敲除编码Vel血型抗原的SMIM1基因。方法设计5条sgRNA序列,构建Cas9-sgRNA共表达质粒,在293T细胞中初步筛选切割效率较高的sgRNA序列。将筛选后的sgRNA通过第二代慢病毒包装系统包装慢病毒并感染K562细胞,提取细胞基因组DNA,进行Sanger测序和TA克隆检测。结果使用易转染的293T细胞建立sgRNA的初步筛选平台,筛选出切割效率较高的sgRNA4序列。CRISPR/Cas9系统成功在K562细胞中SMIM1基因的sgRNA4识别位点发挥基因编辑活性。结论证实了利用CRISPR/Cas9技术在K562细胞中敲除SMIM1基因的可行性,为构建Vel抗原表型阴性的细胞模型奠定基础,也为后续编辑其他血型抗原的基因提供实验依据。     

利用CRISPR/Cas9技术建立SOST荧光报告基因i PSCs细胞系

目的利用CRISPR/Cas9技术构建硬骨素(SOST)基因荧光报告诱导性多能干细胞(i PSCs)细胞株。方法使用PCR检测i PSCs分化过程不同阶段成骨基因的表达。利用CRISPR/Cas9基因编辑技术将p2A-td TomatoNeo质粒转染至i PSCs细胞。使用PCR凝胶电泳检测转染的效果,而后分别在光镜下观察成骨不同阶段i PSCs的形态变化、茜素红染色及SOST-td Tomato荧光表达情况,并利用茜素红染色及PCR评估转染细胞的成骨效果及成骨基因表达情况。结果 PCR检测结果发现,SOST只在骨细胞中稳定表达,可作为骨细胞的标志性基因。利用CRISPR/Cas9技术将td Tomato插入到SOST终止密码子处,转染后的i PSCs细胞株不影响其成骨效果及SOST基因的表达。结论利用CRISPR/Cas9技术能够成功构建td Tomato-SOST荧光报告基因的i PSCs细胞株。     

Knockout of a P‐glycoprotein gene increases susceptibility to abamectin and emamectin benzoate in Spodoptera exigua

P‐glycoprotein [P‐gp or the ATP‐binding cassette transporter B1 (ABCB1)] is an important participant in multidrug resistance of cancer cells, yet the precise function of this arthropod transporter is unknown. The aim of this study was to determine the importance of P‐gp for susceptibility to insecticides in the beet armyworm (Spodoptera exigua) using clustered regularly interspaced short palindromic repeats/CRISPR‐associated 9 (CRISPR/Cas9) gene‐editing technology. We cloned an open reading frame (ORF) encoding the S. exigua P‐gp protein (SeP‐gp) predicted to display structural characteristics common to P‐gp and other insect ABCB1 transporters. A knockout line with a frame shift deletion of four nucleotides in the SeP‐gp ORF was established using the CRISPR/Cas9 gene‐editing system to test its potential role in determining susceptibility to chemical insecticides or insecticidal proteins from the bacterium Bacillus thuringiensis (Bt). Results from comparative bioassays demonstrate that knockout of SeP‐gp significantly increases susceptibility of S. exigua by around threefold to abamectin and emamectin benzoate (EB), but not to spinosad, chlorfenapyr, beta‐cypermethrin, carbosulfan indoxacarb, chlorpyrifos, phoxim, diafenthiuron, chlorfluazuron, chlorantraniliprole or two Bt toxins (Cry1Ca and Cry1Fa). Our data support an important role for SeP‐gp in susceptibility of S. exigua to abamectin and EB and imply that overexpression of SeP‐gp may contribute to abamectin and EB resistance in S. exigua.     

CRISPR/Cas9-Mediated miR-29b Editing as a Treatment of Different Types of Muscle Atrophy in Mice

1. Download : Download high-res image (136KB)
2. Download : Download full-size image

     

Development of novel quality control material based on CRISPR/Cas9 editing and xenografts for MLH1 protein deficiency testing

BackgroundMismatch repair deficiency (dMMR) status induced by MLH1 protein deficiency plays a pivotal role in therapeutic decision‐making for cancer patients. Appropriate quality control (QC) materials are necessary for monitoring the accuracy of MLH1 protein deficiency assays used in clinical laboratories.MethodsCRISPR/Cas9 technology was used to edit the MLH1 gene of GM12878Cas9 cells to establish MLH1 protein‐deficient cell lines. The positive cell lines were screened and validated by Sanger sequencing, Western blot (WB), and next‐generation sequencing (NGS) and were then used to prepare formalin‐fixed, paraffin‐embedded (FFPE) samples through xenografting. These FFPE samples were tested by hematoxylin and eosin (H&E) staining and immunohistochemistry (IHC) for suitability as novel QC materials for MLH1 protein deficiency testing.ResultsWe successfully cultured 358 monoclonal cells, with a survival rate of 37.3% (358/960) of the sorted monoclonal cells. Through Sanger sequencing, cell lines with MLH1 gene mutation were identified. Subsequently, two cell lines with MLH1 protein deficiency were identified by WB and named as GM12878Cas9_6 and GM12878Cas9_10. The NGS results further confirmed that the MLH1 gene mutation in these two cell lines would cause the formation of stop codons and terminate the expression of the MLH1 protein. The H&E staining and IHC results also verified the deficiency of the MLH1 protein, and FFPE samples from xenografts proved their similarity and consistency with clinical samples.ConclusionsWe successfully established MLH1 protein‐deficient cell lines. Followed by xenografting, we developed novel FFPE QC materials with homogenous, sustainable, and typical histological structures advantages that are suitable for the standardization of clinical IHC methods.     

Site‐specific transgenesis of the Drosophila melanogaster Y‐chromosome using CRISPR/Cas9

Despite the importance of Y‐chromosomes in evolution and sex determination, their heterochromatic, repeat‐rich nature makes them difficult to sequence (due, in part, to ambiguities in sequence alignment and assembly) and to genetically manipulate. Therefore, they generally remain poorly understood. For example, the Drosophila melanogaster Y‐chromosome, one of the most extensively studied Y‐chromosomes, is widely heterochromatic and composed mainly of highly repetitive sequences, with only a handful of expressed genes scattered throughout its length. Efforts to insert transgenes on this chromosome have thus far relied on either random insertion of transposons (sometimes harbouring ‘landing sites’ for subsequent integrations) with limited success or on chromosomal translocations, thereby limiting the types of Y‐chromosome‐related questions that could be explored. Here, we describe a versatile approach to site‐specifically insert transgenes on the Y‐chromosome in D. melanogaster via CRISPR/Cas9‐mediated homology‐directed repair. We demonstrate the ability to insert, and detect expression from, fluorescently marked transgenes at two specific locations on the Y‐chromosome, and we utilize these marked Y‐chromosomes to detect and quantify rare chromosomal nondisjunction effects. Finally, we discuss how this Y‐docking technique could be adapted to other insects to aid in the development of genetic control technologies for the management of insect disease vectors and pests.     

CRISPR/Cas系统在感染性疾病诊断中的应用

成簇规律间隔短回文重复序列（CRISPR）/CRISPR相关蛋白（Cas）系统,作为原核生物的适应性免疫防御系统,近年来已经被开发成为一种高效的分子诊断工具,其特异、灵敏、快速、便捷等优势使得其在分子诊断领域,尤其是在感染性疾病的诊断上有着极佳的发展前景。本文旨在对CRISPR/Cas系统在感染性疾病诊断的应用现状、优...     

A novel cell line generated using the CRISPR/Cas9 technology as universal quality control material for KRAS G12V mutation testing

Background

KRAS mutations are the key indicator for EGFR monoclonal antibody‐targeted therapy and acquired drug resistance, and their accurate detection is critical to the clinical decision‐making of colorectal cancer. However, no proper quality control material is available for the current detection methods, particularly next‐generation sequencing (NGS). The ideal quality control material for NGS needs to provide both the tumor mutation gene and the matched background genomic DNA, which is uncataloged in public databases, to accurately distinguish germline polymorphisms and somatic mutations.

Methods

We developed a novel KRAS G12V mutant cell line using the clustered regularly interspaced short palindromic repeat (CRISPR)/CRISPR‐associated protein 9 (Cas9) technique to make up for the deficiencies in existing quality control material and further validated the feasibility of the cell line as quality control material by amplification refractory mutation system (ARMS), Sanger sequencing, digital PCR (dPCR), and NGS.

Results

We verified that the edited cell line specifically had the G12V mutation, and the validation results presented a high consistency among the four methods of detection. The three cell lines screened contained the G12V mutation and the mutation allele fractions of G12V‐1, G12V‐2, and G12V‐3 were 52.01%, 82.06%, and 17.29%, respectively.

Conclusion

The novel KRAS G12V cell line generated using the CRISPR/Cas9 gene editing system is suitable as a quality control material for all current detection methods and provides a new direction in the development of quality control material.

     

Clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR‐associated 9‐mediated mutagenesis of the multiple edematous wings gene induces muscle weakness and flightlessness in Bactrocera dorsalis (Diptera: Tephritidae)

The clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR‐associated 9 (Cas9) system is a versatile, efficient and heritable gene editing tool that can be useful for genome engineering. Bactrocera dorsalis (Hendel) is a major pest of agriculture that causes great economic losses. We used the B. dorsalis multiple edematous wings (Bdmew) gene as the target gene to explore the effectiveness of CRISPR/Cas9 for B. dorsalis genome manipulation. We studied the physiological functions of the Bdmew gene, particularly those related to muscle development. Site‐specific genome editing was feasible using direct microinjection of specific guide RNA and the Cas9‐plasmid into B. dorsalis embryos. Mutation frequencies ranged from 12.1 to 30.2% in the injected generation. Mosaic G0, with the mew mutation, was heritable to the next generation. The G1 displayed a series of defective phenotypes including muscle weakness, flightlessness, failure to eclose, wing folds and unbalanced movement. These results demonstrated that CRISPR/Cas9 can act as a highly specific, efficient, heritable tool for genome manipulation in B. dorsalis and this has significance for gene function research and genetic control of pests. The Bdmew gene possesses key functions in muscle development of B. dorsalis. Bdmew mutations cause a series of serious defects by interfering with muscle development and may provide a means for controlling B. dorsalis via a gene‐based method such as gene drive.     

金纳多注射液对脑缺血/再灌注后caspase-3和caspase-9表达的影响

目的：观察金纳多注射液对大鼠局灶性脑缺血/再灌注后天冬氨酸特异性半胱氨酸蛋白酶-3（caspase-3）和caspase-9蛋白及mRNA表达的影响。方法：40只Wistar雄性大鼠被随机分为假手术组、缺血组、金纳多小剂量治疗组及金纳多大剂量治疗组,每组10只。采用线栓法制备大鼠大脑中动脉闭塞（MCAO）模型。应用原位末端缺刻标记法（TUNEL）检测神经元凋亡;应用免疫组化检测caspase-3和caspase-9的蛋白表达;应用逆转录-聚合酶链反应（RT-PCR）方法检测caspase-3和caspase-9的mRNA表达。结果：与假手术组比较,缺血组、金纳多小剂量治疗组和大剂量治疗组凋亡细胞数以及caspase-3和caspase-9的蛋白及mRNA表达均显著增高（P均〈0.01）;与缺血组比较,金纳多小剂量治疗组和大剂量治疗组凋亡细胞数、caspase-3和caspase-9的蛋白及mRNA表达均显著减少（P均〈0.01）;与金纳多小剂量治疗组比较,金纳多大剂量治疗组凋亡细胞数、caspase-3和caspase-9的蛋白及mRNA表达均明显减少（P均〈0.05）。结论：金纳多注射液能显著减少脑缺血/再灌注后神经元凋亡以及caspase-3、caspase-9的mRNA和蛋白表达,疗效表现为剂量依赖性。