Heterogeneous nuclear RNA (HnRNA) size in developing frog embryos

Abstract

Different stages of developing frog embryos were briefly labeled with [ 3H]uridine and the rapidly labeled RNA was denatured and sized by sucrose density gradient centrifugation. Studies of the accumulation of labeled nuclear and cytoplasmic RNA were employed to learn the extent of turnover of nuclear RNA. Heterogeneous nuclear RNA (HnRNA) size increases during development and this is correlated with an increasing degree of turnover of HnRNA. Size differences of HnRNA exist between axial and belly regions of tailbud embryos. These data suggest that the differences in sizes of nuclear RNA may be important for post-transcriptional processing of HnRNA and control of gene expression in developing frog embryos.