Single adeno-associated virus (AAV)-sized nucleotide for use in CRISPR interference or activation
A nucleic acid molecule is uniquely designed and encodes an entire CRISPRi or CRISPRa system, while being sized for packaging within a single adeno-associated virus (AAV) vector. Examples of the nucleic acid molecule include about 4600 to 4700 base pairs. Examples of the nucleic acid molecule can include a nucleotide encoding a Cas polypeptide; a nucleotide encoding a repressor or an activator domain attached to the nucleotide encoding the Cas polypeptide via a linker; a first promoter operably connected to the nucleotide encoding the repressor or activator domain or the nucleotide encoding the Cas polypeptide; a nucleotide encoding an alpha-helical connecting the nucleotide encoding the Cas polypeptide to a nuclear localization signal (NLS); and a second promoter operably connected to a guide RNA (gRNA).
1. A nucleic acid, comprising:
a) a nucleotide sequence encoding a Cas polypeptide that is a Cas9 polypeptide or a Cas12 polypeptide;
b) a nucleotide sequence encoding a repressor domain or an activator domain attached to the nucleotide sequence encoding the Cas polypeptide via a nucleotide sequence encoding a first linker consisting of 6 to about 60 amino acids;
c) a first promoter operably connected to the nucleotide sequence encoding the repressor or activator domain or the nucleotide sequence encoding the Cas polypeptide, such that the first promoter drives expression of the repressor or activator domain and the Cas polypeptide;
d) a nucleotide sequence encoding a nuclear localization signal (NLS);
e) a nucleotide sequence encoding a second linker, wherein the second linker is alpha-helical when the Cas polypeptide is the Cas9 polypeptide or flexible when the Cas polypeptide is the Cas12 polypeptide, and consists of about 15 to a bout 22 amino acids, wherein the second linker connects the Cas polypeptide to the NLS; and
f) a second promoter operably connected to a nucleotide sequence encoding a guide RNA (gRNA).
2. The nucleic acid of claim 1 , wherein the Cas polypeptide is a Cas9 polypeptide, and wherein the second linker is alpha-helical.
3. The nucleic acid of claim 2 , wherein the Cas9 polypeptide is an SaCas9 polypeptide.
4. The nucleic acid of claim 2 , wherein the Cas9 polypeptide comprises the amino acid sequence of SEQ ID NO: 1.
5. The nucleic acid of claim 2 , wherein the Cas9 polypeptide comprises the amino acid sequence of SEQ ID NO: 3.
6. The nucleic acid of claim 1 , wherein the Cas polypeptide is a Cas12 polypeptide, and wherein the second linker is flexible.
7. The nucleic acid of claim 1 , wherein the repressor domain is selected from the group consisting of KRAB, SRDX, MAD1, and TIEG1.
8. The nucleic acid of claim 1 , wherein the first linker attaches the nucleotide sequence encoding the repressor domain to the nucleotide sequence encoding the Cas polypeptide.
9. The nucleic acid of claim 8 , wherein the first linker consists of about 7 amino acids.
10. The nucleic acid of claim 1 , wherein the first promoter is an RNA polymerase II promoter of about 25 to about 400 nucleotides (base pairs) in length.
11. The nucleic acid of claim 10 , wherein the first promoter is about 350 to about 375 nucleotides in length.
12. The nucleic acid of claim 1 , wherein the second linker that is alpha-helical or flexible comprises a nucleotide sequence encoding the sequence of SEQ ID NO: 9, or SEQ ID NO: 10.
13. The nucleic acid of claim 1 , wherein the NLS has a sequence selected from the group consisting of SEQ ID NO: 11 and SEQ ID NO: 12.
14. The nucleic acid of claim 1 , and further comprising a polyA domain.
15. The nucleic acid of claim 1 , wherein the nucleic acid is about 4600 to 4700 base pairs.
16. A vector comprising the nucleic acid of claim 1 .
17. The vector of claim 16 , wherein the vector is an adeno-associated virus (AAV) vector.