Nucleocytoplasmic Transport of RNA and Protein Synthesis in Developing Brain from Normal and Undernourished Rats

Abstract

We have reported earlier that neonatal undernutrition in the rat produces a transient decrease in brain nuclear RNA synthesis, but a marked and permanent increase in the labeling ratio of nuclear to microsomal RNA following a 1‐h in vivo pulse of labeled precursor (Ramirez de Guglielmone et al., 1974). Although these findings would suggest that posttranscriptional processing and transport of RNA transcripts are permanently affected by this condition, it is also possible that the observed alterations could be due to changes in cytoplasmic RNA metabolism.We report here the effect of neonatal undernutrition on nucleocytoplasmic transport of messenger and ribosomal RNA in a cell‐free system that precludes detectable nuclear lysis. We also attempt to relate alterations in transport to polysomal aggregation and protein synthesis in viva.