Presence of the cap-binding protein in initiation factor preparations from poliovirus-infected HeLa cells.
Crude preparations of initiation factors from mock-infected and poliovirus-infected HeLa cells were analyzed for the presence of proteins which could be cross-linked to the 5' cap group of mRNA. A protein having an apparent molecular weight of 26,000, similar to the cap-binding protein in rabbit reticulocytes described by Sonenberg and Shatkin (Proc. Natl. Acad. Sci. U.S.A. 75:4843-4847, 1978), was found in the ribosomal salt wash from both uninfected and infected cells. Cross-linking of this polypeptide was inhibited by the cap analog m7GMP. In addition, cross-linking of a protein having an approximate molecular weight of 60,000 was similarly inhibited by cap analog. The smaller cap-binding protein fractionated in a 0 to 40% ammonium sulfate precipitate of ribosomal salt wash; the larger protein was found in the 40 to 70% ammonium sulfate fraction. Although the cap-binding proteins were present in both mock-infected and poliovirus-infected ribosomal salt wash, only preparations from uninfected HeLa cells were able to restore translation of capped vesicular stomatitis virus mRNA by extracts prepared from poliovirus-infected cells.
D002352:Carrier Proteins / Q000032:analysis*; D006367:HeLa Cells; D006801:Humans; D008970:Molecular Weight; D010448:Peptide Initiation Factors / Q000032:analysis*; D017955:Poliovirus / Q000254:growth & development*; D014176:Protein Biosynthesis; D039381:RNA Cap-Binding Proteins; D012315:RNA Caps / Q000032:analysis* / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics; D012367:RNA, Viral / Q000235:genetics; D014721:Vesicular stomatitis Indiana virus
D002352:Carrier Proteins; D010448:Peptide Initiation Factors; D039381:RNA Cap-Binding Proteins; D012315:RNA Caps; D012333:RNA, Messenger; D012367:RNA, Viral