The synthesis and processing of ribosomal RNA precursor molecules in yeast

Abstract Experiments are presented which firmly establish the ribosomal precursor nature of the 38-S RNA molecule found in the yeast Schizosaccharomyces pombe by showing that (1) the kinetics of the 38-S molecule are consistent with a precursor-product relationship with ribosomal RNA, (2) the molecule is methylated, (3) the kinetics of methylation are similar to those of uracil labeling, (4) the methyl label can be chased into ribosomal RNA and (5) the cistrons coding for 38-S RNA are homologous to those coding for ribosomal RNA.