Methods for genomic integration in pichia and other host cells
The present invention provides high efficiency targeted and marker-less single, double, triple, quadruple, and quintuple integrations by using CRISPR in host cells, including Pichia.
1. A method of disrupting a target site in a host cell genome, wherein the host cell is Pichia pastoris, the method comprising:
(a) contacting a host cell, which comprises a nucleic acid that encodes an RNA-guided DNA endonuclease, wherein the nucleic acid is integrated in a YKU70 gene, thereby reducing non-homologous and joining (NHEJ) activity in the host cell as compared to a host cell in which the YKU70 gene is intact, with:
(i) a first linear nucleic acid capable of homologous recombination with itself or with one or more additional linear nucleic acids contacted with the host cell, whereby homologous recombination in the host cell results in formation of a circular extrachromosomal nucleic acid comprising a coding sequence for a selectable marker
(ii) a second linear nucleic acid which comprises, from 5′ to 3′, a RNA polymerase II promoter, a first nucleic acid encoding a first ribozyme, a nucleic acid encoding a guide RNA, a second nucleic acid encoding a second ribozyme, and a terminator, wherein the guide RNA guides the DNA nuclease to the target site; and
(b) selecting a transformed host cell expressing the selectable marker, wherein the host cell has reduced NHEJ activity.
2. The method of claim 1 , wherein the method further comprises contacting the host cell with a donor DNA molecule capable homologous recombination with the target site, whereby homologous recombination in the host cell results in integration of the donor DNA molecule at the target site.
3. The method of claim 2 , wherein the step of contacting includes contacting the cell with two or more donor DNA molecules capable of homologous recombination with different target sites, whereby homologous recombination in the host cell results in integration of the donor DNA molecules at the different target sites.
4. The method of claim 2 , wherein the donor DNA molecule comprises a nucleic acid sequence encoding an antibody.
5. The method of claim 1 , wherein the step of contacting includes contacting the cell with two or more second linear nucleic acid molecules, wherein each second linear nucleic acid molecule comprises a nucleic acid encoding a different guide RNA, which guides the DNA nuclease to a different target site.
6. The method of claim 1 , wherein the nucleic acid encoding the RNA-guided DNA endonuclease is operably linked to a Pichia pPGK1 promoter.
7. The method of claim 1 , wherein the RNA-guided DNA endonuclease is Cas9.
8. The method of claim 7 , wherein the nucleic acid sequence encoding the Cas9 is codon optimized for expression in Saccharomyces.