Processing of ribosomal RNA precursor in isolated insect nuclei

In isolated nuclei, derived from developing silk moth wings pulse-labeled with H³-uridine, progressive redistribution of label occurs among various classes of ribosomal RNA during a period of $\text{in}$,$\text{vitro}$ culture in non-radioactive medium. The results indicate that the $\text{in}$,$\text{vivo}$ labeled 39s precursor can be processed into smaller ribosomal RNA species in a cell-free system.