CRISPR-Based Modular Assembly for High-Throughput Construction of a UAS-cDNA/ORF Plasmid Library

We present a protocol for CRISPR-based modular assembly (CRISPRmass), a method for high-throughput construction of UAS-cDNA/ORF plasmid library in Drosophila using publicly available cDNA/ORF resources. CRISPRmass can be applied to editing various plasmid libraries.

Functional genomic screening offers a powerful approach to approach gene function, and relies on the construction of genome wide plasmid libraries. Conventional approaches for plasmid library construction are time consuming and laborious. To address this question, we develop a simple and efficient matter.

CRISPR based modular assembly are CRISPR mass. So the leverage of shared vital sequences of cDNA or OFSIB by CRISPR CAS9, and subsequent insertion of UAS modules by assembly. The procedure of construction of a genome Y plasmid library.

By crystal mass, it's standardized as massively paralyzed, two step test to reactions before bacterial transformation. Crystal mass allows the simple, fast, efficient, and cause effective construction of various plasmid libraries. It can also be applied to editing various genome wide, plasmid libraries in general, and it's an alternative to gateway technology in high supreme plasmid library editing, paving the way for the global studies of biological networks.

To perform the parallel, two-step test tube reactions of the CRISPR based modular assembly, or CRISPR mass, proceed to cleave the identical vector backbones of the cDNA ORF plasmids by CAS9 sgRNA in test tube reactions step one. To do so, arrange properly labeled, 0.2 milliliter tubes in an aluminum cooling block on ice. Prepare the master mix for N number of reactions by mixing appropriate amounts of CAS9, sgRNA, CAS9 buffer, and DEPC treated water.

Once the components of the master mix are added together, vortex the same to ensure proper mixing. Then spin down the mix and aliquot two microliters of the master mix to each 0.2 milliliter tube. Next, add 0.4 microliters of 0.019 micromolar cDNA, ORF plasmid to each tube.

Incubate cleavage reactions at 37 degrees Celsius for one hour. In the following test tube reaction, step two, proceed to insert a vector specific UAS module into the resultant CAS9 linearized, cDNA ORF plasmids. To set up the 1.4 microliter single step reaction for each sample, arrange the labeled 0.2 milliliter tubes in an aluminum cooling block on ice.

Prepare the master mix for N number of reactions by mixing appropriate amounts of UAS module and single step reaction assembly master mix. Vortex the mix well before spinning it down, then aliquot 0.77 microliters of the master mix to each tube. Add 0.7 microliters of CAS9 linearized, cDNA ORF plasmid to the aliquot in each tube, and incubate reactions at 50 degrees Celsius for one hour.

To transform the UAS cDNA ORF plasmids products, obtained from the CRISPR based modular assembly into escherichia coli, pre-chill 10 microliter tips at four degrees Celsius. Also, pre-chill 1.5 milliliter tubes in an aluminum cooling block on ice. After thawing competent E coli cells on ice for five minutes, add an aliquot of 10 microliters of the cells to each pre-chilled 1.5 milliliter tube.

Then add one microliter of the UAS cDNA ORF plasmid products to each tube containing 10 microliters of competent cells. Swirl the tube gently to mix and place it on ice for 30 minutes. Incubate the tubes at 42 degrees Celsius in a water bath for one minute.

Then immediately chill on ice for two minutes. Add 100 microliters of SOC medium pre-warmed to 37 degrees Celsius to each tube at room temperature, and incubate the tubes in a shaking incubator at 250 RPM and 37 degrees Celsius for one hour. Next, warm the LB plates, containing an antibiotic, corresponding to the UAS module's antibiotic resistance gene to 37 degrees Celsius.

Spread the cells onto the warm plates and incubate them at 37 degrees Celsius overnight.