Two forms of purified m7G-cap binding protein with different effects on capped mRNA translation in extracts of uninfected and poliovirus-infected HeLa cells.

作者：Stanley M. Tahara, Mark A. Morgan, Aaron J. Shatkin · 发表于：Journal of Biological Chemistry · 年份：1981 · DOI：10.1016/s0021-9258(18)43324-8 · 被引用次数：226 · 研究领域：RNA and protein synthesis mechanisms、RNA modifications and cancer、RNA Research and Splicing

Eukaryotic mRNA cap binding proteins were purified from ribosomal salt wash in the presence of protease inhibitors by sucrose gradient sedimentation and m7GDP-Sepharose affinity chromatography. Rabbit reticulocyte and erythrocyte proteins with sedimentation constants of less than 6 S yielded a approximately 24,000-dalton cap binding protein. It stimulated capped mRNA translation in extracts of uninfected HeLa cells but did not restore capped mRNA function in extracts prepared from poliovirus-infected cells. Restoring and stimulatory activities both were associated with a larger, approximately 8-10 S complex that included the approximately 24,000-dalton polypeptide and several higher molecular mass components. The same two translational activities were also obtained in a slightly smaller approximately 5-7 S complex from uninfected HeLa cells but were absent from poliovirus-infected cell preparations.