Methods and compositions for generating CRISPR guide RNA libraries
The disclosure generally relates to compositions, polynucleotides, kits, methods, and systems for generating clustered regularly interspaced short palindromic repeats (CRISPR) libraries. Disclosed are polynucleotides encoding for a constant region of a CRISPR single guide RNA (sgRNA) or CRISPR targeting RNA (crRNA) having a non-palindromic recognition site for a type II restriction enzyme oriented in a manner recognized by the type II restriction enzyme for cutting a site past an end of the polynucleotide. The methods include using the polynucleotide to prepare CRISPR libraries.
1. A polynucleotide comprising: a sequence encoding for a constant region comprising a protein binding segment of an RNA component of a CRISPR complex, the sequence comprising: a non-palindromic recognition sequence for a type restriction enzyme configured to cleave at least 17 nucleotides outside of the non-palindromic recognition sequence, the non-palindromic recognition sequence being oriented such that, in the presence of the type restriction enzyme, a DNA cleavage domain of the type II restriction enzyme is positioned outside of the constant region.
2. The polynucleotide of claim 1 , wherein the polynucleotide is double-stranded with sense and antisense strands and the non-palindromic recognition sequence is oriented that, when in the presence of the type II restriction enzyme, the DNA cleavage domain of the type restriction enzyme is positioned at one of: a first location upstream from a 5′ end of the sense strand and a second location downstream from a 3′ end of the sense strand.
3. The polynucleotide of claim 1 , wherein the encoded constant region comprising the non-palindromic recognition sequence is configured to be incorporated within a secondary structure of the RNA component of the CRISPR complex.
4. The polynucleotide of claim 1 , further comprising a second sequence capable of hybridizing to the non-palindromic recognition sequence.
5. The polynucleotide of claim 4 , wherein the encoded constant region comprising the non-palindromic recognition sequence and the second sequence hybridize to form a secondary structure of the constant region.
6. The polynucleotide of claim 1 , wherein the polynucleotide is double-stranded and further comprises a modification selected from at least one modified sugar moiety, at least one modified internucleotide linkage, at least one modified nucleotide, and combinations thereof.
7. The polynucleotide of claim 6 , wherein the at least one modified internucleotide linkage is selected from the group of phosphorothioate, alkylphosphonate, phosphorodithioate, alkylphosphonothioate, phosphoramidate, carbamate, carbonate, phosphate triester, acetamidate, carboxymethyl ester, and combinations thereof.
8. The polynucleotide of claim 1 , wherein the non-palindromic recognition sequence is capable of binding to at least one type H restriction enzyme selected from the group consisting of NmeAIII, MmeI, CstMI, EcoP15I, ApyPI, AquII, AquIII, AquIV, CdpI, CstMI, DraRI, DrdIV, EsaSSI, MaqI, NhaXI, N1aCI, PlaDI, PspOMII, PspPRI, RceI, RpaB5I, SdeAI, SpoDI, BsbI, and combinations thereof.
9. The polynucleotide of claim 1 , wherein the polynucleotide is operably linked to a second polynucleotide, wherein, when in the presence of the type restriction enzyme, the second polynucleotide is cleaved at least 17 nucleotides from the non-palindromic recognition sequence.
10. The polynucleotide of claim 9 , wherein cleavage by the type II restriction enzyme generates a variable region, wherein the variable region comprises a DNA hybridizing segment of the RNA component of the CRISPR complex.
11. The polynucleotide of claim 10 , operably linked to a third polynucleotide comprising a promoter sequence recognized by an RNA polymerase, wherein the promoter is capable of directing the RNA polymerase to transcribe the RNA component of the CRISPR complex.
12. A kit for generating CRISPR guide RNA (gRNA) libraries comprising a polynucleotide comprising: a sequence encoding for a constant region comprising a protein binding segment of an RNA component of a CRISPR complex, the constant region comprising: a non-palindromic recognition sequence for a type II restriction enzyme configured to cleave at least 17 nucleotides outside of the non-palindromic recognition sequence, the non-palindromic recognition sequence being oriented that, when in the presence of the type II restriction enzyme, a DNA cleavage domain of the type II restriction enzyme is positioned outside of the constant region.
13. The kit of claim 12 further comprising the type II restriction enzyme.
14. The kit of claim 13 , wherein the type H restriction enzyme is selected from the group consisting of NmeAIII, MmeI, CstMI, EcoP15I, ApyPI, AquII, AquIII, AquIV, CdpI, CstMI, DraRI, DrdIV, EsaSSI, MaqI, NhaXI, N1aCI, PlaDI, PspOMII, PspPRI, RceI, RpaB5I, SdeAI, SpoDI, BsbI, and combinations thereof.
15. The kit of claim 12 further comprising a solid support capable of immobilizing the polynucleotide to a surface of the sod support by chemical attachment, high binding affinity or oligonucleotide hybridization.
16. The kit of claim 12 further comprising a promoter polynucleotide recognized by an RNA polymerase.