Transcript mapping and processing of mitochondrial RNA in Dictyostelium discoideum

Abstract

The circular mitochondrial genome of Dictyostelium discoideum has a size of 55, 564 base pairs. We present here a complete and detailed transcription map of the mitochondrial DNA. Eight major, polycistronic transcripts encoding polypeptides, ribosomal RNAs and interspersed transfer RNAs were identified in Northern hybridization studies. Most of these polycistronic transcripts are subsequently processed into smaller mono-, di- or tricistronic RNAs. In some cases, the maturation involves endonucleolytic cleavage of the transcripts using transfer RNAs as excision signals. Primer extension experiments mapped the 5′ ends of the transcripts, which may represent transcription initiation sites. Two ..