Kinetoplast RNA of Leishmania tarentolae

RNA has been isolated from highly purified kinetoplast-mitochondrial fractions of Leishmania tarentolae, and shown to consist of two major species that sediment at 9S and 12S in sucrose and also several additional low molecular weight species which were visualized by gel electrophoresis. The in vivo transcription of 9S and 12S RNAs was inhibited by ethidium bromide and rifampin, and was fairly insensitive to low actinomycin D and camptothecin. The 9S and 12S RNAs were isolated by acrylamide gel electrophoresis or by sedimentation in sucrose. Both RNAs contained approximately 80% A + U and did not contain long stretches of poly(A). The 9S and 12S RNAs were found to hybridize selectively to the maxicircle sequences of the kinetoplast DNA, implying that the maxicircle, and not the minicircle, represents the informational mitochondrial DNA in the kinetoplast.