Subcellular redistribution of seryl-transfer RNA during estrogen-induced phosvitin synthesis and specificity of the estrogen effect

The estrogen-induced hepatic synthesis of the serine-rich protein, phosvitin, in chickens is accompanied by an increase in the serine acceptance of total hepatic tRNA, which is limited to two sering isoacceptors. To investigate the role of the tRNA alterations in the synthesis of phosvitin, the relative amounts of various seryl-tRNA species in isolated nuclei and in free and membrane-bound ribosomes were determined. Estrogen treatment causes a shift in the subcellular distribution of hepatic seryl-tRNA. Of the four serine isoacceptors, the amount of tRNASerAGU,AGC was specifically increased in nuclei and in membrane-bound ribosomes. Changes in total hepatic tRNA occurring during physiologic estrogenization were compared with those occurring by varying steroid hormones, times after estrogen administration, estrogen doses, animal ages, and tissue types. The changes observed demonstrate that the seryl-tRNA alterations are closely correlated with the synthesis of phosvitin. The coincident change in seryl-tRNA levels and in phosvitin synthesis, together with the specific change in cellular localization, suggests that the amount and subcellular distribution of each tRNA species are separately controlled in a manner dependent upon its frequency of use in translation.