| Autor: |
Hiremath LS; Department of Biochemistry, College of Medicine, University of Kentucky, Lexington 40536-0084., Hiremath ST, Rychlik W, Joshi S, Domier LL, Rhoads RE |
| Jazyk: |
angličtina |
| Zdroj: |
The Journal of biological chemistry [J Biol Chem] 1989 Jan 15; Vol. 264 (2), pp. 1132-8. |
| Abstrakt: |
Complementary DNA for human eukaryotic initiation factor 4E (eIF-4E) was transcribed in vitro and the transcripts used to direct protein synthesis in a cell-free reticulocyte translation system. The predominant translation product was 25 kDa, was bound to a m7GTP-Sepharose affinity column, and was specifically eluted with m7GTP. Both phosphorylated (P) and unphosphorylated (U) forms of eIF-4E were synthesized, and the P/U ratio increased as a function of incubation time in the reticulocyte lysate system. Both forms were quantitatively retained on m7GTP-Sepharose. When translation reactions were resolved on sucrose density gradients, the 35S-labeled eIF-4E sedimented predominantly at 3-4 S. However, in the presence of edeine or guanylyl imidodiphosphate, both of which cause accumulation of 48 S initiation complexes, eIF-4E was detected in the 48 S region. In the presence of sparsomycin, used to accumulate 80 S initiation complexes, no eIF-4E was observed in the 80 S region. No change in the eIF-4E distribution was caused by m7GTP. These results are consistent with a model whereby eIF-4E is transferred to the 43 S initiation complex together with mRNA and is released from the initiation complex when the 60 S ribosomal subunit joins. |
| Databáze: |
MEDLINE |
| Externí odkaz: |
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