Powerhouse in Flux: Changes in Mitochondrial RNA Processing During Starvation in Trypanosoma cruzi

Abstract

T. cruzi is an important human pathogen. During starvation in the insect hind gut that leads to metacyclogenesis, or the differentiation of the parasite into a life stage which can be transmitted to humans, many mitochondrial RNAs encoding electron transport chain subunits are increased in abundance. Most edited mitochondrial mRNAs are increased in abundance while their pre-edited counterparts are not, pointing to a change in the process of editing. Both the cause and effect some of these changes in mitochondrial RNA abundances were explored. Mitochondrially enriched RNAs were collected and sequenced. Future analysis of the sequencing data will be used to explore changes in editing during starvation. Additionally, both of the mitochondrial rRNAs are increased in abundance during starvation. Northern blot analysis of density gradient fractions revealed that the additional transcripts of mitochondrial rRNA produced during starvation are incorporated into functional ribosomes. Because of the increase in abundances of mitochondrial mRNAs and ribosomes, the physiology of the electron transport chain was investigated to see if starvation induces a change in the electron transport chain function toward more efficient ATP generation. Analysis of oxygen consumption showed that T. cruzi do shift toward more efficient ATP production via the electron transport chain during starvation. These findings point toward a model whereby starvation induces changes in the electron transport chain physiology, which requires increased gene expression of the mitochondrial genome, resulting in greater production of ATP by the electron transport chain in T. cruzi.