[Informosome formation in maturing amphibian oocytes].

[14C]Uridine and/or RNA-binding [3H]protein preparations were microinjected into the oocytes of Rana temporaria frog. It was shown that both labelled compounds are incorporated into RNP particles with the buoyant density in CsCl characteristic of informosomes and with a homogeneous sedimentation distribution in sucrose gradients. Injection of actinomycin D into recipient oocyte leads to inhibition of synthesis of the informosome RNA component as well as to the incorporation of RNA-binding [3H] proteins into free informosomes. The results obtained provide experimental proofs for the assumption that the RNA-binding proteins under study form complexes predominantly with newly synthesized RNA.