Biochemical Research on Oogenesis

Abstract
TRNA makes up 30-40% of total RNA in previtellogenic oocytes of X. laevis. The bulk of tRNA is associated with 5-S RNA and 2 proteins in a high-molecular-weight complex sedimenting at 42 S. All kinds of tRNA are present in the 42-S particles and all of them sediment coincidently. Particle tRNA is fully charged in vivo. During purification of the 42-S particles tRNA becomes partially uncharged. When purified particles are incubated in vitro with amino acids and ATP a charging reaction occurs without disruption of the nucleoprotein complex. Many aminoacyl-tRNA synthetases co-sediment with the 42-S particles. Complete aminoacylation of tRNA within the storage particles may result from the activity of particle-bound aminoacyl-tRNA synthetases.