Project Reference: TRG27-BIO-SS1

Project title: Decoding mitochondrial RNA-processing machinery of the apicomplexan parasite Toxoplasma gondii

Project outline

Background: Mitochondrial gene expression is essential for energy production in almost all eukaryotes. Apicomplexan parasites, including Toxoplasma and Plasmodium, rely on a single mitochondrion for survival and infection. However, their mitochondria are highly divergent, with a ~6 kb genome lacking tRNA genes, encoding only three proteins, and containing highly fragmented ribosomal RNAs (rRNAs) that assemble into a functional mitoribosome.

Our recent work determining the high-resolution cryoEM structure of Toxoplasma mitochondrial ribosome revealed the most fragmented ribosome known in nature, assembled from 53 discrete rRNA fragments (PMID:39827269) generated through extensive post-transcriptional processing. However, the factors responsible for this processing remain unknown. Their extreme divergence precludes discovery by homology-based approaches, necessitating an unbiased proteomic strategy to identify novel mitochondrial RNA-processing factors and complexes.

We will:

Aim 1: Define the mitochondrial RBPome of Toxoplasma. Orthogonal Organic Phase Separation (OOPS) coupled with quantitative mass spectrometry will generate the first comprehensive RNA-binding proteome of Toxoplasma. Mitochondrial RNA biogenesis factors will be prioritised by integrating RNA-binding, localisation, structural data as well as conservation across apicomplexan and wider myzozoan lineage to identify novel RNA-processing proteins.

Aim 2: Define and validate the candidates involved in mitochondrial RNA-processing. Candidate factors identified in Aim-1 will be functionally characterised using conditional genetics, transcriptomics and interaction proteomics to determine their roles in mitochondrial RNA maturation and ribonucleoprotein complex assembly.

Beyond advancing fundamental organelle biology, this work will uncover parasite-specific mechanisms of mitochondrial gene expression that represent attractive targets for future antiparasitic intervention.

Principal Supervisor

Dr Shikha Shikha

Email address: shikha.shikha@glasgow.ac.uk

Department / Partner Institute: Biochemistry

Website: n/a

BBSRC strategic theme

Understanding the rules of life