title: Expanding the CRISPR imaging toolset with Staphylococcus aureus Cas9 for simultaneous imaging of multiple genomic loci.
abstract: In order to elucidate the functional organization of the genome, it is vital to directly visualize the interactions between genomic elements in living cells. For this purpose, we engineered the Cas9 protein from Staphylococcus aureus (SaCas9) for the imaging of endogenous genomic loci, which showed a similar robustness and efficiency as previously reported for Streptococcus pyogenes Cas9 (SpCas9). Imaging readouts allowed us to characterize the DNA-binding activity of SaCas9 and to optimize its sgRNA scaffold. Combining SaCas9 and SpCas9, we demonstrated two-color CRISPR imaging with the capability to resolve genomic loci spaced by <300 kb. Combinatorial color-mixing further enabled us to code multiple genomic elements in the same cell. Our results highlight the potential of combining SpCas9 and SaCas9 for multiplexed CRISPR-Cas9 applications, such as imaging and genome engineering.
authors.affiliation: Department of Pharmaceutical Chemistry, University of California, San Francisco, San Francisco, CA 94143, USA.
authors.forename: Baohui
authors.initials: B
authors.lastname: Chen
authors.affiliation: Department of Pharmaceutical Chemistry, University of California, San Francisco, San Francisco, CA 94143, USA.
authors.forename: Jeffrey
authors.initials: J
authors.lastname: Hu
authors.affiliation: Department of Cellular and Molecular Pharmacology, University of California San Francisco, San Francisco, CA 94158, USA.
authors.forename: Ricardo
authors.initials: R
authors.lastname: Almeida
authors.affiliation: Graduate Program of Bioengineering, University of California, San Francisco, San Francisco, CA 94143, USA.
authors.forename: Harrison
authors.initials: H
authors.lastname: Liu
authors.affiliation: Department of Cell and Tissue Biology, University of California, San Francisco, San Francisco, CA 94143, USA.
authors.forename: Sanjeev
authors.initials: S
authors.lastname: Balakrishnan
authors.affiliation: MRC Laboratory of Molecular Cell Biology, University College London, London, WC1E 6BT, UK.
authors.forename: Christian
authors.initials: C
authors.lastname: Covill-Cooke
authors.affiliation: Department of Cellular and Molecular Pharmacology, University of California San Francisco, San Francisco, CA 94158, USA Howard Hughes Medical Institute, University of California, San Francisco, San Francisco, CA 4143, USA.
authors.forename: Wendell A
authors.initials: WA
authors.lastname: Lim
authors.affiliation: Department of Pharmaceutical Chemistry, University of California, San Francisco, San Francisco, CA 94143, USA Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, CA 94143, USA bo.huang@ucsf.edu.
authors.forename: Bo
authors.initials: B
authors.lastname: Huang
mesh_terms: D000818:Animals; D064130:CRISPR-Associated Proteins / Q000235:genetics*; D064113:CRISPR-Cas Systems / Q000235:genetics*; D002460:Cell Line; D064112:Clustered Regularly Interspaced Short Palindromic Repeats / Q000235:genetics*; D004268:DNA-Binding Proteins / Q000235:genetics; D016678:Genome / Q000235:genetics; D057809:HEK293 Cells; D006801:Humans; D051379:Mice; D013211:Staphylococcus aureus / Q000201:enzymology* / Q000235:genetics; D013297:Streptococcus pyogenes / Q000201:enzymology* / Q000235:genetics
chemical_list: D064130:CRISPR-Associated Proteins; D004268:DNA-Binding Proteins