A novel fragmented mitochondrial genome in the protist pathogenToxoplasma gondiiand related tissue coccidia

Abstract

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Complexome profile of Toxoplasma gondii mitochondria identifies divergent subunits of respiratory chain complexes including new subunits of cytochrome bc1 complex

“…All of the 14 recently identified nuclear encoded complex IV subunits [7,34] were identified and co-migrated on the gel, with peak abundance observed in gel slice 19 (Figs 2D, S2C and S2D). Using the sequence of the T. gondii mitochondrial genome from a recent study [42], we also detected the two mitochondrially encoded complex IV subunits, CoxI and CoxIII (Fig 2D), which have not been previously detected in large-scale proteomic studies. The Toxoplasma complex IV is estimated to have a total mass of~460 kDa (S5 Table), smaller than the 600 kDa estimated by Seidi et al, 2018 [7], but substantially larger than the 200 kDa of mammals and yeast [43,44].…”

“…The mitochondrial genome of Toxoplasma has recently been sequenced [42]. It contains three protein encoding genes, which encode three mETC subunits: CoxI, CoxIII and CytB.…”

“…To assign peptide sequences the Proteome Discoverer (Thermo Fisher Scientific) software was used with Mascot 2.4 (Matrix Science Ltd.) configured to use a custom database containing Toxoplasma gondii GT1 proteins (ensembl proteins toxoplasma_gon-dii_gt1_gca_00149715.TGGT1.pep.all.fa last updated 04.03.2020) in addition to Chlorocebus sabaeus ensembl proteins (Chlorocebus_sabaeus.ChlSab1.1.pep.all last updated 05.03.2020) with the manual addition of the protein sequences for T. gondii mitochondrial encoded proteins CoxI, CoxIII and CytB [42], plus NCBI reference sequence XP_007959728. A separate copy of the database was further modified to truncate sequences for F 1 F o ATP synthase subunits alpha and beta and succinate dehydrogenase subunit A to before a peptide that is common between the species, to avoid erroneous apparent co-migration.…”

Third-generation sequencing revises the molecular karyotype for Toxoplasma gondii and identifies emerging copy number variants in sexual recombinants

“…2A), whereas there were no contigs in the other RH assemblies with any resemblance to a mitochondrial genome (likely due to being filtered out during sequence analysis or submission). Given the complexities of the mitochondrial genome and its assembly for T. gondii (as evidenced by recent work from the Kissinger group using Oxford Nanopore technology) (Namasivayam et al 2021), we did not perform any extensive analyses of these sequences but include them in our assemblies submitted to the NCBI BioProject database (https://www.ncbi.nlm.nih.gov/bioproject/) under accession number PRJNA638608 with the annotation "location = mitochondria." De novo assembly of multiple T. gondii strains, their sexual recombinants, and N. caninum To determine whether the Chr VIIb/VIII fusion was unique to TgRH88 or was also present in other isolates, we sequenced and assembled genomes of TgME49, TgCTG, TgME49×TgCTG F1 progeny (CL13, S27, S21, S26, and D3X1), and N. caninum Liverpool strain (Table 1).…”

Depletion of voltage-dependent anion channel (VDAC) ofToxoplasma gondiiaffects multiple mitochondrial functions, but not calcium signalling

“…In plant cells VDAC is also thought to be required for import of tRNAs (Salinas et al, 2014(Salinas et al, , 2006. The mitochondrial genome of T. gondii is severely reduced and encodes only subunits of the electron transport chain and rRNAs, which require tRNA import for translation (Esseiva et al, 2004;Lacombe et al, 2019;Namasivayam et al, 2020;Pino et al, 2010). However, we do not see any changes in the membrane potential of the mitochondria upon VDAC depletion, providing indirect evidence that the electron transport chain remains functional, thus likely no defect in tRNA import occurs.…”