Developing targeted genome regulation approaches holds much promise for
accelerating trait discovery and development in agricultural biotechnology. Clustered
Regularly Interspaced Palindromic Repeats (CRISPRs)/CRISPR associated (Cas) system
provides bacteria and archaea with an adaptive molecular immunity mechanism against
invading nucleic acids through phages and conjugative plasmids. The type II
CRISPR/Cas system has been adapted for genome editing purposes across a variety of
cell types and organisms. Recently, the catalytically inactive Cas9 (dCas9) protein
combined with guide RNAs (gRNAs) were used as a DNA-targeting platform to
modulate the expression patterns in bacterial, yeast and human cells. Here, we employed
this DNA-targeting system for targeted transcriptional regulation in planta by developing
chimeric dCas9-based activators and repressors. For example, we fused to the C-terminus
of dCas9 with the activation domains of EDLL and TAL effectors, respectively, to
generate transcriptional activators, and the SRDX repression domain to generate
transcriptional repressor. Our data demonstrate that the dCas9:EDLL and dCas9:TAD
activators, guided by gRNAs complementary to promoter elements, induce strong
transcriptional activation on episomal targets in plant cells. Moreover, our data suggest
that the dCas9:SRDX repressor and the dCas9:EDLL and dCas9:TAD activators are
capable of markedly repressing or activating, respectively, the transcription of an
endogenous genomic target. Our data indicate that the CRISPR/dCas9:TFs DNA
targeting system can be used in plants as a functional genomic tool and for
biotechnological applications.
Date of Award | May 2014 |
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Original language | English (US) |
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Awarding Institution | - Biological, Environmental Sciences and Engineering
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Supervisor | Magdy Mahfouz (Supervisor) |
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- CRISPR/Cas 9
- Transcriptional regulation
- activation
- dCas9
- dCas9 - chimeric proteins
- repression