A Genome-wide CRISPR Screen in Toxoplasma Identifies Essential Apicomplexan Genes.
Apicomplexan parasites are leading causes of human and livestock diseases such as malaria and toxoplasmosis, yet most of their genes remain uncharacterized. Here, we present the first genome-wide genetic screen of an apicomplexan. We adapted CRISPR/Cas9 to assess the contribution of each gene from the parasite Toxoplasma gondii during infection of human fibroblasts. Our analysis defines ∼200 previously uncharacterized, fitness-conferring genes unique to the phylum, from which 16 were investigated, revealing essential functions during infection of human cells. Secondary screens identify as an invasion factor the claudin-like apicomplexan microneme protein (CLAMP), which resembles mammalian tight-junction proteins and localizes to secretory organelles, making it critical to the initiation of infection. CLAMP is present throughout sequenced apicomplexan genomes and is essential during the asexual stages of the malaria parasite Plasmodium falciparum. These results provide broad-based functional information on T. gondii genes and will facilitate future approaches to expand the horizon of antiparasitic interventions.
Whitehead Institute for Biomedical Research, Cambridge, MA 02142, USA.
Saima M
SM
Sidik
Whitehead Institute for Biomedical Research, Cambridge, MA 02142, USA.
Diego
D
Huet
Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
Suresh M
SM
Ganesan
Department of Microbiology and Immunology, University of Michigan School of Medicine, Ann Arbor, MI 48109, USA.
My-Hang
MH
Huynh
Whitehead Institute for Biomedical Research, Cambridge, MA 02142, USA; Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139 USA; Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA.
Tim
T
Wang
Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
Armiyaw S
AS
Nasamu
Whitehead Institute for Biomedical Research, Cambridge, MA 02142, USA.
Prathapan
P
Thiru
Department of Pathology, Microbiology and Immunology, University of California, Davis, Davis, CA 95616, USA.
Jeroen P J
JPJ
Saeij
Department of Microbiology and Immunology, University of Michigan School of Medicine, Ann Arbor, MI 48109, USA.
Vern B
VB
Carruthers
Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
Jacquin C
JC
Niles
Whitehead Institute for Biomedical Research, Cambridge, MA 02142, USA. Electronic address: lourido@wi.mit.edu.
Sebastian
S
Lourido
D016782:Apicomplexa / Q000235:genetics*; D002478:Cells, Cultured; D057167:Claudins / Q000235:genetics / Q000378:metabolism; D064112:Clustered Regularly Interspaced Short Palindromic Repeats; D005347:Fibroblasts / Q000469:parasitology; D018503:Genome, Protozoan / Q000235:genetics; D055106:Genome-Wide Association Study; D006790:Host-Parasite Interactions; D006801:Humans; D016778:Malaria, Falciparum / Q000469:parasitology / Q000503:physiopathology; D010963:Plasmodium falciparum / Q000235:genetics; D015800:Protozoan Proteins / Q000235:genetics* / Q000378:metabolism*; D014122:Toxoplasma / Q000235:genetics*; D014123:Toxoplasmosis / Q000469:parasitology / Q000503:physiopathology
D057167:Claudins; D015800:Protozoan Proteins
Apicomplexan parasites; eukaryotic pathogen; genome-wide CRISPR screen; host-cell invasion; host-pathogen interactions; malaria; toxoplasmosis