Translation of mRNAs for subunits of chloroplast coupling factor 1 in spinach
AUTOR(ES)
Watanabe, Akira
RESUMO
The chloroplast coupling factor 1 consists of five nonidentical subunits, three of which (α, β, and ε subunits) have been shown in several laboratories to be synthesized within chloroplasts. The site of synthesis of the remaining two (γ and δ subunits) was investigated by analyzing products directed by spinach leaf RNAs in wheat germ and reticulocyte translation systems in vitro. It was found that poly(A)+ RNA directs the synthesis of two distinct polypeptides, one of which is immunochemically related to the γ subunit but is 4,000 daltons larger. The other shares antigenic sites with the δ subunit but is 8,000 daltons larger. When wheat germ or reticulocyte translation systems were programmed with RNAs from purified chloroplasts, the only products related to CF1 that we could detect were a putative precursor of β, 2,000 daltons larger than the mature subunit, and some smaller polypeptides, which appear to be incomplete translation products of β. From these results it appears likely that the γ and δ subunits are synthesized in the cytoplasm as larger precursors and that β is synthesized within the chloroplast as a precursor.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=347109Documentos Relacionados
- Initiation factor-independent translation of mRNAs from Gram-positive bacteria.
- A nuclear mutation in maize blocks the processing and translation of several chloroplast mRNAs and provides evidence for the differential translation of alternative mRNA forms.
- Xenopus fibrinogen: characterization of the mRNAs for the three subunits.
- Initiation complex formation on Euglena chloroplast 30S subunits in the presence of natural mRNAs.
- Proteolytic cleavage of initiation factor eIF-4 gamma in the reticulocyte lysate inhibits translation of capped mRNAs but enhances that of uncapped mRNAs.
