TY - JOUR
T1 - A novel fragmented mitochondrial genome in the protist pathogen Toxoplasma gondii and related tissue coccidia
AU - Namasivayam, Sivaranjani
AU - Baptista, Rodrigo P.
AU - Xiao, Wenyuan
AU - Hall, Erica M.
AU - Doggett, Joseph S.
AU - Troell, Karin
AU - Kissinger, Jessica C.
N1 - Funding Information:
We thank Silvia Moreno for providing mitochondrial-enriched fractions of T. gondii; Stuart Ralph for sharing his T. gondii PRU Δku80 direct RNA strand sequence data; David Sibley for providing the T. gondii ME49 strain used in the genome project; Tobias Lilja and Faruk Dube for assistance with ONT sequencing; and Yiran Li for assistance with plots. This work benefited from discussions with Kissinger Research Group members both past and present. This work was supported in part through National Institutes of Health funding (NIH R01 AI068908) and resources from the Georgia Advanced Computing Resource Center. J.S.D. received support from BX002440 from the U.S. Department of Veterans Affairs Biomedical Laboratory Research.
Publisher Copyright:
© 2021 Namasivayam et al.
PY - 2021
Y1 - 2021
N2 - Mitochondrial genome content and structure vary widely across the eukaryotic tree of life, with protists displaying extreme examples. Apicomplexan and dinoflagellate protists have evolved highly reduced mitochondrial genome sequences, mtDNA, consisting of only three cytochrome genes and fragmented rRNA genes. Here, we report the independent evolution of fragmented cytochrome genes in Toxoplasma and related tissue coccidia and evolution of a novel genome architecture consisting minimally of 21 sequence blocks (SBs) totaling 5.9 kb that exist as nonrandom concatemers. Single-molecule Nanopore reads consisting entirely of SBs ranging from 0.1 to 23.6 kb reveal both whole and fragmented cytochrome genes. Full-length cytochrome transcripts including a divergent coxIII are detected. The topology of the mitochondrial genome remains an enigma. Analysis of a cob point mutation reveals that homoplasmy of SBs is maintained. Tissue coccidia are important pathogens of man and animals, and the mitochondrion represents an important therapeutic target. The mtDNA sequence has been elucidated, but a definitive genome architecture remains elusive.
AB - Mitochondrial genome content and structure vary widely across the eukaryotic tree of life, with protists displaying extreme examples. Apicomplexan and dinoflagellate protists have evolved highly reduced mitochondrial genome sequences, mtDNA, consisting of only three cytochrome genes and fragmented rRNA genes. Here, we report the independent evolution of fragmented cytochrome genes in Toxoplasma and related tissue coccidia and evolution of a novel genome architecture consisting minimally of 21 sequence blocks (SBs) totaling 5.9 kb that exist as nonrandom concatemers. Single-molecule Nanopore reads consisting entirely of SBs ranging from 0.1 to 23.6 kb reveal both whole and fragmented cytochrome genes. Full-length cytochrome transcripts including a divergent coxIII are detected. The topology of the mitochondrial genome remains an enigma. Analysis of a cob point mutation reveals that homoplasmy of SBs is maintained. Tissue coccidia are important pathogens of man and animals, and the mitochondrion represents an important therapeutic target. The mtDNA sequence has been elucidated, but a definitive genome architecture remains elusive.
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U2 - 10.1101/GR.266403.120
DO - 10.1101/GR.266403.120
M3 - Article
C2 - 33906963
AN - SCOPUS:85106068409
VL - 31
SP - 852
EP - 865
JO - Genome Research
JF - Genome Research
SN - 1088-9051
IS - 5
ER -