The Year in CRISPRs - 7

CRISPR-Cas9
Edits the Epigenome
B

est known as a gene-editing system,
CRISPR-Cas9 is also being used to edit the
epigenome, turning on specific gene promoters and enhancers. The trick is to silence CRISPRCas9's DNA-cutting mechanism. Instead, the
CRISPR-Cas9 machinery is used to deliver an
enzyme, an acetyltransferase, which adds
artificial epigenetic marks to the DNA packaging
proteins known as histones.

Gene-editing technologies have been used
in several investigations of transcriptional
regulation, but with mixed results. For example,
some technologies intended for transcriptional
7

| GENengnews.com

control do not enzymatically modulate the
chromatin state. They remodel the epigenome
indirectly, and so they do not allow specific
epigenetic markers to be evaluated.
A more direct and more potent approach
has been described by researchers from Duke
University. They report that they have designed
a fusion protein of a nuclease null deactivated
Cas9 (dCas9) with the catalytic histone
acetyltransferase core domain of the human
E1A-associated protein p300, a highly conserved
acetyltransferase involved in a wide range of
cellular processes. They reasoned that

recruitment of an acetyltransferase by dCas9
to a genomic target site would directly modulate
epigenetic structure.
The Duke scientists introduced their
epigenome-editing system April 6 in Nature
Biotechnology, in an article entitled, "Epigenome
editing by a CRISPR-Cas9-based acetyltransferase
activates genes from promoters and enhancers."
The article's authors indicated that their fusion
protein catalyzes acetylation of histone H3 lysine
27 at its target sites, leading to robust transcriptional activation of target genes from promoters
and proximal and distal enhancers.


http://www.GENengnews.com

The Year in CRISPRs

Table of Contents for the Digital Edition of The Year in CRISPRs

Contents
The Year in CRISPRs - 1
The Year in CRISPRs - 2
The Year in CRISPRs - 3
The Year in CRISPRs - Contents
The Year in CRISPRs - 5
The Year in CRISPRs - 6
The Year in CRISPRs - 7
The Year in CRISPRs - 8
The Year in CRISPRs - 9
The Year in CRISPRs - 10
The Year in CRISPRs - 11
The Year in CRISPRs - 12
The Year in CRISPRs - 13
The Year in CRISPRs - 14
The Year in CRISPRs - 15
The Year in CRISPRs - 16
The Year in CRISPRs - 17
The Year in CRISPRs - 18
The Year in CRISPRs - 19
The Year in CRISPRs - 20
The Year in CRISPRs - 21
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