CRISPR/Cas systems for genomic modification and gene modulation
The invention relates to engineered CRISPR/Cas9 systems for genomic modification and regulation of gene expression in mammalian cells. The specification describes the design and validation of polynucleotides encoding the Streptococcus pyogenes ( S. pyogenes ) Cas9 gene and protein and variants of that protein, where the nucleotide sequence has been optimized for expression in mammalian cells, and also modified by fused sequences that enhance various aspects of the CRISPR/Cas system. The specification also describes systems for RNA-guided genome engineering and gene regulation in mammalian cells, including human cells.
1. A recombinant polynucleotide comprising:
(i) a nucleotide sequence selected from SEQ ID NOs: 3, 4 and 6-10,
(ii) conservative variants of (i) which are at least 50% identical in nucleotide sequence compared to the nucleotide sequence of (i), and further wherein said conservative variants encode a functional Cas9 polypeptide comprising an amino acid sequence selected from:
(A) the amino acid sequence of SEQ ID NO: 1,
(B) a variant of the amino acid sequence of SEQ ID NO: 1 having a D10A mutation, or
(C) a variant of the amino acid sequence of SEQ ID NO: 1 having D10A and H840A mutations, or
(iii) at least 100 contiguous nucleotides of SEQ ID NO: 3, 7 or 9, and further wherein said recombinant polynucleotide encodes a functional Cas9 polypeptide selected from:
(A) SEQ ID NO: 1,
(B) a variant of SEQ ID NO: 1 having a D10A mutation,
(C) a variant of SEQ ID NO: 1 having D10A and H840A mutations, or
(D) a conservative variant of (A), (B) or (C).
2. The recombinant polynucleotide of claim 1 wherein the polynucleotide comprises the nucleotide sequence of either SEQ ID NO: 3, 7 or 9, and wherein the polynucleotide further comprises at least one operably linked nucleotide sequence encoding a nuclear localization signal.
3. An expression construct comprising the recombinant polynucleotide of claim 1 .
4. An expression construct comprising the recombinant polynucleotide of claim 1 , where the expression construct is a mammalian expression construct.
5. An expression construct comprising the recombinant polynucleotide of claim 1 where the expression construct is a human expression construct.
6. An mRNA expression construct comprising: (i) a recombinant polynucleotide of claim 1 , and (ii) an in vitro transcription promoter element that is operably linked to the recombinant polynucleotide of claim 1 .
7. An mRNA expression construct comprising: (i) a recombinant polynucleotide of claim 1 , and (ii) a bacteriophage promoter element that is operably linked to the recombinant polynucleotide of claim 1 .
8. A recombinant polynucleotide encoding a polypeptide comprising an amino acid sequence selected from SEQ ID NOs: 5 and 13, and conservative variants thereof.
9. An expression construct comprising:
(a) a first recombinant polynucleotide comprising:
(A) a nucleotide sequence selected from SEQ ID NOs: 3, 4 and 6-10,
(B) conservative variants of (A) which are at least 50% identical in nucleotide sequence compared to the nucleotide sequence of (A), and further wherein said conservative variants encode a functional Cas9 polypeptide comprising an amino acid sequence selected from:
(i) the amino acid sequence of SEQ ID NO: 1,
(ii) a variant of the amino acid sequence of SEQ ID NO: 1 having a D10A mutation, or
(iii) a variant of the amino acid sequence of SEQ ID NO: 1 having D10A and H840A mutations, or
(C) at least 100 contiguous nucleotides of SEQ ID NO: 3, 7 or 9, and further wherein said first recombinant polynucleotide encodes a polypeptide selected from:
(i) SEQ ID NO: 1,
(ii) a variant of SEQ ID NO: 1 having a D10A mutation,
(iii) a variant of SEQ ID NO: 1 having D10A and H840A mutations, or
(iv) a conservative variant of (i), (ii) or (iii); and
(b) a second recombinant polynucleotide encoding a guide RNA, said guide RNA comprising (i) a crRNA-tracrRNA scaffold polynucleotide, and (ii) a targeting sequence corresponding to a genomic target of interest, wherein the targeting sequence is operably linked to the crRNA-tracrRNA scaffold polynucleotide.
10. The expression construct of claim 9 , wherein the expression construct is a mammalian expression construct.
11. The expression construct of claim 9 , wherein the first recombinant polynucleotide comprises nucleotide sequence encoding at least one nuclear localization signal.