Transcriptional and post-transcriptional in organello labelling of Trypanosoma brucei mitochondrial RNA.

In organello labelling of Trypanosoma brucei mitochondrial (mt) RNA was characterised with respect to nucleotide requirements and drug sensitivity. Mitochondrial transcriptional activity is maximal in the presence of all ribonucleoside-triphosphate NTPs, and can be inhibited by UTP depletion. Mitochondrial transcription can also be partially inhibited by actinomycin D (actD) or ethidium bromide (EtBr). Post-transcriptional UTP incorporation is insensitive to actinomycin D or ethidium bromide. Proteins were identified that interact with transcriptional and post-transcriptionally labelled RNAs, and confirm the in vitro RNA-binding properties discovered for a number of T. brucei mt proteins. These experiments reveal new strategies for studying mt transcription and processing in T. brucei mitochondria.