Two forms of purified m7G-cap binding protein with different effects on capped mRNA translation in extracts of uninfected and poliovirus-infected HeLa cells.
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.
D000818:Animals; D001798:Blood Proteins / Q000032:analysis; D002352:Carrier Proteins / Q000235:genetics*; D002472:Cell Transformation, Viral; D006367:HeLa Cells / Q000378:metabolism; D006801:Humans; D008970:Molecular Weight; D017955:Poliovirus / Q000235:genetics*; D014176:Protein Biosynthesis; D039381:RNA Cap-Binding Proteins; D012315:RNA Caps / Q000235:genetics*; D011817:Rabbits; D012156:Reticulocytes / Q000378:metabolism; D012845:Sindbis Virus / Q000235:genetics; D014764:Viral Proteins / Q000096:biosynthesis
D001798:Blood Proteins; D002352:Carrier Proteins; D039381:RNA Cap-Binding Proteins; D012315:RNA Caps; D014764:Viral Proteins