CRISPR-Cas systems and methods for altering expression of gene products, structural information and inducible modular Cas enzymes
The invention provides for systems, methods, and compositions for altering expression of target gene sequences and related gene products. Provided are structural information on the Cas protein of the CRISPR-Cas system, use of this information in generating modified components of the CRISPR complex, vectors and vector systems which encode one or more components or modified components of a CRISPR complex, as well as methods for the design and use of such vectors and components. Also provided are methods of directing CRISPR complex formation in eukaryotic cells and methods for utilizing the CRISPR-Cas system. In particular the present invention comprehends the engineering of optimized modular CRISPR-Cas enzyme systems.
1. A polynucleotide encoding
i) a first Cas protein fusion construct comprising a first fragment of a Cas protein attached to a first half of an inducible dimer;
ii) a second Cas protein fusion construct comprising a second fragment of the Cas protein attached to a second half of the inducible dimer; or
iii) both the first and second Cas protein fusion constructs, the first Cas protein fusion construct comprising the first fragment of the Cas protein attached to the first half of an inducible dimer and the second Cas protein fusion construct comprising the second fragment of the Cas protein attached to the second half of the inducible dimer,
wherein the first Cas protein fusion construct is operably linked to one or more nuclear localization signals,
wherein the second Cas protein fusion construct is operably linked to one or more nuclear export signals,
wherein contact with an inducer energy source brings the first and second halves of the inducible dimer together,
wherein bringing the first and second halves of the inducible dimer together allows the first and second fragments of the Cas protein to form a complex with a guide RNA to constitute a functional CRISPR-Cas system,
wherein the guide RNA comprises a guide sequence capable of hybridizing to a target sequence in a genomic locus of interest in a cell, and
wherein the functional CRISPR-Cas system binds to the target sequence.
2. A vector for delivery of the first Cas protein fusion construct operably linked to one or more nuclear localization signals, and/or the second Cas protein fusion construct operably linked to one or more nuclear export signals, according to claim 1 .
3. An isolated eukaryotic host cell or cell line transformed with the vector of claim 2 .
4. A transgenic non-human organism transformed with the vector of claim 2 , or the progeny thereof.
5. A transgenic non-human organism expressing the Cas fusion protein constructs of claim 1 , or the progeny thereof.
6. A model non-human organism which constitutively expresses the Cas fusion protein constructs of claim 1 .
7. The polynucleotide of claim 1 , wherein the first half of the inducible dimer comprises an FK506 binding protein (FKBP) or FK506 binding protein 12 (FKBP12), and the second half of the inducible dimer comprises FKBP-rapamycin binding domain (FRB).