Cytoplasmic nonpolysomal ribonucleoprotein particles in sea urchin embryos and their relationship to protein synthesis

AUTOR(ES)

Dworkin, Mark B.

RESUMO

We have examined the relationship between the newly synthesized mRNA that enters polysomes in sea urchin embryos and the messengerlike RNA that enters the pool of ribosome-free ribonucleoprotein particles (free RNPs or informosomes). Although the RNA in the free RNPs turns over 25% more rapidly than in the polysomes, labeling kinetics indicate that the RNA containing poly(A) [poly(A)(+)RNA] and the RNA not containing poly(A) [poly(A)(-)RNA] within each cytoplasmic compartment have very similar half-lives. The poly(A)(+)RNA from both free RNPs and polysomes binds ribosomes almost equally well in a reticulocyte lysate, and this binding is sensitive to inhibitors of initiation. The poly(A)(-)RNA from polysomes initiates as well as poly(A)(+)RNA; however, poly(A)(-)RNA from free RNPs is only half as efficient in binding to ribosomes, and by this criterion is only 50% mRNA.

Documentos Relacionados

• Nonrandom distribution of histone mRNAs into polysomes and nonpolysomal ribonucleoprotein particles in sea urchin embryos.
• Stabilization of tubulin mRNA by inhibition of protein synthesis in sea urchin embryos.
• ENZYMES OF DNA SYNTHESIS IN NUCLEI OF SEA URCHIN EMBRYOS*
• Spermidine is bound to a unique protein in early sea urchin embryos.
• MITOTIC ABNORMALITIES IN SEA URCHIN EMBRYOS EXPOSED TO DACTINOMYCIN*