Published: July 1st, 2021
Presented here is a protocol of Helicoverpa armigera (Hübner) embryo microinjection and knockout mutant identification created by CRISPR/Cas9 genome editing. Mutant insects enable further research of gene function and interaction among different genes in vivo.
The cotton bollworm, Helicoverpa armigera, is one of the most destructive pests in the world. A combination of molecular genetics, physiology, functional genomics, and behavioral studies has made H. armigera a model species in Lepidoptera Noctuidae. To study the in vivo functions of and interactions between different genes, clustered regularly interspaced short palindromic repeats (CRISPR)/ associated protein 9 (Cas9) genome editing technology is a convenient and effective method used for performing functional genomic studies. In this study, we provide a step-by-step systematic method to complete gene knockout in H. armigera using the CRISPR/Cas9 system. The design and synthesis of guide RNA (gRNA) are described in detail. Then, the subsequent steps consisting of gene-specific primer design for guide RNA (gRNA) creation, embryo collection, microinjection, insect rearing, and mutant detection are summarized. Finally, troubleshooting advice and notes are provided to improve the efficiency of gene editing. Our method will serve as a reference for the application of CRISPR/Cas9 genome editing in H. armigera as well as other Lepidopteran moths.
The application of genome editing technology provides an efficient tool to achieve target-gene mutants in diverse species. The emergence of the clustered regularly interspaced short palindromic repeats (CRISPR)/associated protein 9 (Cas9) system provides a novel method to manipulate genomes1. The CRISPR/Cas9 system consists of a guide RNA (gRNA) and the Cas9 endonuclease2,3, while the gRNA can be further divided into two parts, a target complementary CRISPR RNA (crRNA) and a trans-activating crRNA (tracrRNA). The gRNA integrates with Cas9 endonuclease and forms a ribonucleoprotein (RNP)....
1. Design of gene-specific primers and preparation of sgRNA
This protocol provides detailed steps for obtaining gene knock-out lines of H. armigera using CRISPR/Cas9 technology. The representative results obtained by this protocol are summarized for gDNA selection, embryo collection and injection, insect rearing, and mutant detection.
In this study, the target site of our gene of interest was located in its second exon (Figure 2A). This site was hig.......
The application of the CRISPR/Cas9 system has provided powerful technical support for the analysis of gene function and interaction among various genes. The detailed protocol we present here demonstrates the generation of a homozygote mutant in H. armigera via CRISPR/Cas9 genome editing. This reliable procedure provides a straightforward way for directed gene mutagenesis in H. armigera.
The choice of CRISPR target sites could affect the mutagenesis efficiency
|2kb DNA ladder
|World Precision Instrucments
|referred to as "capillary glass" in the protocol
|Double Sided Tape
|Minnesota Mining and Manufacturing Corporation
|Eppendorf FemtoJet 4i Microinjector
|Eppendorf InjectMan 4 micromanipulator
|Eppendorf Microloader Pipette Tips
|GeneArt Precision gRNA Synthesis Kit
|Thermo Fisher Scientific
|PrimeSTAR HS (Premix)
|Takara Biomedical Technology
|used for mutant detection
|Sutter Micropipette Puller
|Sutter Instrument Company
|TIANamp Genomic DNA Kit
|TrueCut Cas9 Protein v2
|Thermo Fisher Scientific
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