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January 2020

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CRISPR-Mediated Activation of Endogenous Gene Expression in the Postnatal Heart. Circulation Research. DZHK authors: Eric Schoger, Lavanya M. Iyer, Claudia Noack, Shirin Doroudgar, Wolfram-H. Zimmermann, Laura C. Zelarayan,

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The CRISPR/Cas9 gene scissors have broad applications in cardiovascular research. Cas9 is a protein that finds, binds and cuts a target sequence in the genome using a small RNA molecule (gRNA). A modified Cas9 variant that has lost its DNA-cutting function (dCas9) is used as a DNA-binding platform. Researchers of the DZHK have developed a mouse model which specifically expresses the dCas9 protein fused to a gene activation domain (VPR) in myocardial cells with the aim of enabling gene activation in myocardial cells.

The dCas9-VPR protein is directed by gRNA to a gene regulatory region (promoter region) and induces the expression of the target gene. The work was a cooperation of the DZHK partner sites Göttingen and Heidelberg and was supported by a research stay at the UTSW Medical Center in Dallas within the "Visiting Scientist" program.

Using this model, the scientists activated a known transcription factor that causes heart muscle remodelling and observed a reduction in heart function. The activation of a second gene allowed investigations on the titratability of the system as well as on the efficiency for a gene that is otherwise low expressed at the time of investigation. They analyzed the specificity of the method by examining dCas9-VPR bound DNA fragments and found a high binding capacity at the targeted promoter regions.
With this tool it is possible to achieve controlled gene activation in heart muscle cells and to test potential candidate genes with high precision for therapeutic intervention in heart failure.