[Synthesis of RNA and protein during oogenesis and early embryogenesis of Acheta domestica]

During maturation of the cricket oocyte principally r-RNA and little t-RNA are formed. Furthermore it is possible to label an RNA-fraction that can be referred to as m-RNA according to its velocity of sedimentation in a sucrose density gradient.Data are discussed showing that the r-RNA formed during oogenesis is probably stable at least up to the stage of yolk cleavage.The incorporation of labelled aminoacids into dechorionated eggs starts during very early cleavage stages, whereas an incorporation of labelled uridine is scarcely detectable. This indicates that although protein synthesis proceeds, practically no measurable RNA synthesis exists. From these data it is concluded that in the cricket egg - just as in amphibian and sea urchin eggs - the first protein synthesis proceeds mainly on preexisting m-RNA.