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

III organello labelling of Trypanosoma brucei mitochondrial (mt) RNA was ch aracterised with respect to nucleotide requirements and drug sensitivity. M itochondrial transcriptional activity is maximal in the presence of all rib onucleoside-triphosphate NTPs, and can be inhibited by UTP depletion. Mitoc hondrial transcription can also be partially inhibited by actinomycin D (ac tD) or ethidium bromide (EtBr). Post-transcriptional UTP incorporation is i nsensitive to actinomycin D or ethidium bromide. Proteins were identified t hat 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 studyin g mt transcription and processing in T. brucei mitochondria. (C) 2000 Publi shed by Elsevier Science Ltd on behalf of the Australian Society for Parasi tology Inc. All rights reserved.