Translational capacity of sheep oocytes microinjected with messenger RNA.
Sheep oocytes were microinjected with tobacco mosaic virus RNA (TMV-RNA) and isotopically labelled with L-[35S]methionine. Total incorporation of labelled methionine was similar in TMV-RNA-injected and in carrier-injected control oocytes, whether injections were performed during the period of high protein synthesis at maturation or during the period of reduced synthesis at a time equivalent to the mid-cleavage transition (48 h after germinal vesicle breakdown). Varying the amount of TMV-RNA injected from 2.5 to 10 pg had little effect on the overall level of amino acid incorporation. Furthermore TMV-RNA appeared to be very stable in oocytes and eggs; the proportion of total polypeptide synthesis directed by TMV-RNA did not diminish during the first 48 h after injection. Synthesis of most endogenous proteins was uniformly reduced to compensate for the synthesis of TMV-polypeptides. Our results suggest, therefore, that the translational capacity of sheep oocytes is fully saturated during maturation.
Moor
R M
RM
Department of Molecular Embryology, Institute of Animal Physiology and Genetics Research, Babraham, Cambridge, UK.
Powell
D J
DJ
D000818:Animals; D005260:Female; D008715:Methionine / Q000378:metabolism; D008845:Microinjections; D009865:Oocytes / Q000502:physiology*; D014176:Protein Biosynthesis; D012333:RNA, Messenger / Q000235:genetics*; D012756:Sheep
D012333:RNA, Messenger; D008715:Methionine