Evidence that the methylation inhibitor cycloleucine causes accumulation of a discrete ribosomal RNA precursor in hamster mitochondria

A novel RNA fraction, 'Cy RNA,' that accumulates in mitochondria when hamster cells are treated with the methylation inhibitor cycloleucine, has been characterized by high resolution acrylamide gel electrophoresis and DNA-RNA hybridization. Cy RNA ran in gels as a discrete band, with an apparent chain length of 2 600. It hybridized specifically to restriction fragments containing genes for the mitochondrial ribosomal RNAs. We infer that Cy RNA is a discrete polycistronic ribosomal RNA precursor transcript, whose processing is dependent on normal methylation.