Characterization of wheat germ protein synthesis initiation factor eIF-4C and comparison of eIF-4C from wheat germ and rabbit reticulocytes.

Abstract

Eukaryotic protein synthesis initiation factor (eIF)-4C was purified from wheat germ and the molecular weight was calculated to be approximately 19,000 by SDS-polyacrylamide gel electrophoresis. A similar molecular weight was determined by gel filtration chromatography indicating that wheat germ eIF-4C is functional as a single polypeptide chain. An efficient in vitro translation system dependent upon the addition of eIF-4C was developed. This system was used to determine the concentrations of eIF-4C required for the half-maximal rate of translation of satellite tobacco necrosis virus RNA, alfalfa mosaic virus RNA 4, and barley alpha-amylase mRNA. No significant differences in the concentrations of eIF-4C required for the translation of these mRNAs were observed, although differences were noted for eIF-4A and eIF-4F. This finding suggests that eIF-4C is not involved in the binding of mRNA to 40 S ribosomal subunits. In heterologous assays, rabbit reticulocyte eIF-4C was as active as wheat germ eIF-4C in the wheat germ eIF-4C-dependent system. In addition, wheat germ eIF-4C substituted for rabbit reticulocyte eIF-4C in in vitro assay systems from rabbit reticulocytes. These results indicate that eIF-4C from wheat and rabbit contain conserved functional domains.

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Cite this paper

@article{Timmer1993CharacterizationOW, title={Characterization of wheat germ protein synthesis initiation factor eIF-4C and comparison of eIF-4C from wheat germ and rabbit reticulocytes.}, author={Radbout Timmer and Si{\^a}n Lax and Don L Hughes and William C. Merrick and J M Ravel and Karen S. Browning}, journal={The Journal of biological chemistry}, year={1993}, volume={268 33}, pages={24863-7} }