RNA-directed DNA cleavage by the Cas9-crRNA complex
Isolation or in vitro assembly of the Cas9-crRNA complex of the Streptococcus thermophilus CRISPR3/Cas system and use for cleavage of DNA bearing a nucleotide sequence complementary to the crRNA and a proto-spacer adjacent motif. Methods for site-specific modification of a target DNA molecule using an RNA-guided DNA endonuclease comprising at least one RNA sequence and at least one of an RuvC active site motif and an HNH active site motif; for conversion of Cas9 polypeptide into a nickase cleaving one strand of double-stranded DNA by inactivating one of the active sites (RuvC or HNH) in the polypeptide by at least one point mutation; for assembly of active polypeptide-polyribonucleotides complex in vivo or in vitro; and for re-programming a Cas9-crRNA complex specificity in vitro or using a cassette containing a single repeat-spacer-repeat unit.
1 . A composition comprising:
at least one plasmid for preparing a recombinant Cas9-crRNA complex, the at least one plasmid comprising:
a polynucleotide sequence encoding a Cas9 protein containing a mutation in a RuvC nuclease domain or an HNH nuclease domain of the Cas9 protein, wherein the Cas9 protein comprises a fusion polypeptide comprising at least one additional amino acid sequence;
a polynucleotide sequence encoding a tracrRNA; and
a polynucleotide sequence encoding an engineered crRNA, wherein the sequence of the engineered crRNA is heterologous to the sequence of the Cas9 protein and reprogrammed to guide the recombinant Cas9-crRNA complex to a region comprising a site in a target DNA molecule; and
the target DNA molecule, wherein the region of the target DNA molecule comprises at least 20 nucleotides complementary to the engineered crRNA;
wherein the recombinant Cas9-crRNA complex is assembled in vitro; and
wherein the recombinant Cas9-crRNA complex is capable of cleaving the site of the target DNA molecule.
2 . The composition of claim 1 , wherein the target DNA molecule is a double-stranded DNA molecule.
3 . The composition of claim 1 , wherein the target DNA molecule is a plasmid DNA.
4 . The composition of claim 1 , wherein the mutation of the Cas9 protein is a point mutation in the RuvC nuclease domain corresponding to D31A of SEQ ID NO: 1.
5 . The composition of claim 1 , wherein the Cas9 protein contains a point mutation in the HNH nuclease domain of the Cas9 protein.
6 . The composition of claim 1 , wherein the mutation of the Cas9 protein is a point mutation in the HNH nuclease domain corresponding to N891A of SEQ ID NO: 1.
7 . The composition of claim 1 , wherein the sequence encoding the engineered crRNA and the sequence encoding the tracrRNA are produced by in vitro transcription or chemical synthesis, and the sequence encoding the Cas9 protein is produced by recombinant DNA technology or chemical synthesis.
8 . The composition of claim 1 , wherein the at least one plasmid is isolated from a genetically modified microorganism.
9 . The composition of claim 1 , wherein the recombinant Cas9-crRNA complex consists essentially of the Cas9 protein, the tracrRNA, and the engineered crRNA.
10 . The composition of claim 1 , wherein the composition does not comprise RNaselll.
11 . A composition comprising:
a first plasmid for preparing a recombinant Cas9-crRNA complex, the first plasmid comprising:
a polynucleotide sequence encoding a tracrRNA; and
a polynucleotide sequence consisting essentially of one spacer flanked on either side by a repeat, wherein the sequence encodes an engineered crRNA
reprogrammed to guide the recombinant Cas9-crRNA complex to a region comprising a site in a target DNA molecule;
a second plasmid comprising a polynucleotide sequence encoding a Cas9 protein, wherein the Cas9 protein comprises a fusion polypeptide comprising at least one additional amino acid sequence; and
the target DNA molecule, wherein the region of the target DNA molecule comprises at least 20 nucleotides complementary to the engineered crRNA;
wherein the first plasmid does not encode a Cas9 protein wherein the recombinant Cas9-crRNA complex is assembled in vitro.
12 . The composition of claim 11 , wherein the first plasmid consists essentially of the sequence encoding the tracrRNA and the sequence encoding the engineered crRNA.
13 . The composition of claim 11 , wherein the target DNA molecule is a double-stranded DNA molecule.
14 . The composition of claim 11 , wherein the composition does not comprise RNaselll.
15 . A composition comprising:
a first plasmid for preparing a recombinant Cas9-crRNA complex, the first plasmid comprising:
a polynucleotide sequence encoding a tracrRNA; and
a polynucleotide sequence consisting essentially of one spacer flanked on either side by a repeat, wherein the sequence encodes an engineered crRNA reprogrammed to guide the recombinant Cas9-crRNA complex to a region comprising a site in a target DNA molecule;
wherein the first plasmid does not encode a Cas9 protein;
a second plasmid for preparing the recombinant Cas9-crRNA complex, the second plasmid comprising a polynucleotide sequence encoding a Cas9 protein, wherein the Cas9 protein comprises a fusion polypeptide comprising at least one additional amino acid sequence; and
the target DNA molecule, wherein the region of the target DNA molecule comprises at least 20 nucleotides complementary to the engineered crRNA;
wherein the recombinant Cas9-crRNA complex is assembled in vitro; and
wherein the recombinant Cas9-crRNA complex is capable of cleaving the site of the target DNA molecule.
16 . The composition of claim 15 , wherein the target DNA molecule is a double-stranded DNA molecule.
17 . The composition of claim 15 , wherein the composition does not comprise RNaselll.