In vivo synthesis of mitochondrial RNA immediately after fertilization in Paracentrotus lividus

: In the present paper the in vivo incorporation of 3H-guanosine into mitochondrial RNA and of 35S-methionine into mitochondrial ribosomal proteins of Paracentrotus lividus embryos have been studied. Mitochondrial rRNA and low molecular weight RNA are newly synthesized in vivo by Paracentrotus lividus embryos as early as at 2-cell stage. Labeled RNA but not labeled proteins have been extracted from the mitochondrial ribosomes of the Paracentrotus lividus embryos at 32-cell stage.