We build biobricks for our project. These parts cover all aspects in our project,
including Cas13d protein expression and purification, Cas13d’s cleavage activity
verification in virto, construction of HEK293T-ACE2 sable cell line and the lentivirus
carried CRISPR-Cas13d system to degrade mRNA of ACE2.
Part List
Part Name (Link) | Description | Type |
---|---|---|
BBa_K3760000 | Rfx Cas13d coding sequence | coding |
BBa_K3760001 | 6 X His tag-Rfx Cas13d | Composite |
BBa_K3760002 | EF-1α promoter+RfxCas13d+NLS | Composite |
BBa_K3760003 | 17 promoter t hACE target RNA coding sequence | Coding |
BBa_K3760004 | hACE2-T2A-mRFP | Composite |
BBa_K3760005 | RfxCas13d-nACE2-sgRNA1 | RNA |
BBa_K3760006 | RfxCas13d-nACE2-gRNA2 | RNA |
BBa_K3760007 | RfxCas13d-nACE2-sgRNA3 | RNA |
BBa_K3760008 | T7 promorter-sgRNA1-Synthesis | Other |
BBa_K3760009 | T7 promorter-sgRNA2-Synthesis | Other |
BBa_K3760010 | T7 promorter-sgRNA3-Synthesis | Other |
BBa_K3760011 | SgRNA expression cassette | Composite |
1.Cas13 protein
To knock down the expression of ACE2, we choose RfxCas13d protein as our
cleavage effector which is found in Ruminococcus flavefaciens. To obtain
this protein with high purity and activity, we designed biobricks to express
RfxCas13d protein. Meanwhile, we attached 6×His tag to make it can be purified
by Ni-NTA purification.BBa_K3760000, BBa_K3760001[1].
2.ACE2 target sequence
To test the cleavage activity of our CRISPR-Cas13d system in virto,
we built BBa_K3760003 which cotains coding sequence of ACE2.
It is the template for mRNA of ACE2 in vitro synthesis.
3.sgRNA for RfxCas13d
The sgRNA is an oligonucleotide chain, it can combine with Cas13 protein and guide
Cas13 to find the target single-stranded RNA. It consists of two parts, DR sequence
and spacer. The DR sequence is determined by Cas13 protein. We built BBa_K3760005,
BBa_K3760006, BBa_K3760007 to guide our Cas13d protein to target the mRNA of ACE2.
4.Construction of HEK293T-ACE2 stable cell line
To construct HEK293T stable cell line as target cell in cell experiment, we built
BBa_K3760004 which will be used to package lentivirus. This part cotains ACE2, T2A and mRFP.
5.Knockdown of ACE2
To knock down the expression of ACE2, we built BBa_K3760002 and
BBa_K3760011 which cotains RfxCas13d and sgRNA expression cassette[2].
References
[1]Konermann S, Lotfy P, Brideau NJ, Oki J, Shokhirev MN, Hsu PD. Transcriptome Engineering with RNA-Targeting Type VI-D CRISPR Effectors. Cell. 2018 Apr 19;173(3):665-676.e14. doi: 10.1016/j.cell.2018.02.033. Epub 2018 Mar 15. PMID: 29551272; PMCID: PMC5910255.
[2]Chuang YF, Wang PY, Kumar S, Lama S, Lin FL, Liu GS. Methods for in vitro CRISPR/CasRx-Mediated RNA Editing. Front Cell Dev Biol. 2021 Jun 11;9:667879. doi: 10.3389/fcell.2021.667879. PMID: 34178991; PMCID: PMC8226256.