New technique for activating multiple genes at the same time

By creating a powerful new gene regulation system called CRISPR-on, Whitehead Institute researchers now have the ability to increase the expression of multiple genes simultaneously and precisely manipulate each gene’s expression level. The system is effective in both mouse and human cells as well as in mouse embryos.

“CRISPR-on is a tool that will be very useful for studying many biological processes, particularly for studying gene functions and gene networks,” says Whitehead Founding Member Rudolf Jaenisch. “In contrast to RNA interference, which is commonly used to inactivate gene activity, the CRISPR-on system allows activation of cellular genes. The technology substantially expands our ability to change gene expression in cultured cells and animals..”

The system, called CRISPR-on, is a modified version of CRISPR/Cas (for “clustered regularly interspaced short palindromic repeat/CRISPR associated”), which taps into a bacterial defense system against viral intruders. CRISPR/Cas relies on an enzyme, Cas9, which cuts DNA at locations specified by single guide RNAs (sgRNAs). For CRISPR-on, the Whitehead team modified the Cas9 enzyme by eliminating its ability to cleave DNA and adding a transcription activation domain. The resulting enzyme can increase gene expression without permanently changing the DNA.

Whitehead Institute researchers created the enzyme used in CRISPR-on by fusing the Cas9 protein to a VP160 domain containing 10 tandem copies of VP16 motifs. The VP160 domain acts as a transcriptional activation domain. Image: Courtesy of Cell Research

Multiplexed activation of endogenous genes by CRISPR-on, an RNA-guided transcriptional activator system

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