Transcription of the human mitochondrial genome and correct processing of the two long polycistronic transcripts are crucial for oxidative phosphorylation. According to the tRNA punctuation model, nucleolytic processing of these large precursor transcripts occurs mainly through the excision of the tRNAs that flank most rRNAs and mRNAs. However, some mRNAs are not punctuated by tRNAs, and it remains largely unknown how these non-canonical junctions are resolved. The FASTK family proteins are emerging as key players in non-canonical RNA processing.

By generating human cell lines carrying single or combined knockouts of several FASTK family members and producing comprehensive mitochondrial transcriptome analyses, Jean-Claude Martinou‘s group and collaborators revealed that the FASTK protein family members are crucial regulators of non-canonical junction and non-coding mitochondrial RNA processing.

The article was published in PLOS Genetics on Nov. 8th, 2021.