Eukaryotic Translation Initiation Factor 3F (EIF3F)

Eukaryotic initiation factor-3 (eIF3) is the largest of the eIFs and consists of at least 10 nonidentical subunits in mammals. See p66 (EIF3S7). By searching EST databases with the partial protein sequences of rabbit p66, p47, and p40, Asano et al. (1997) identified cDNAs encoding the human homologs. Although the predicted 357-amino acid human p47 protein has a calculated molecular mass of 37.5 kD, it migrates at 47 kD by SDS-PAGE. The authors attributed the anomalous migration to the high proline content of the N-terminal region of p47. Sequence analysis revealed that the N-terminal halves of p40 and p47 are similar to each other and are related to the mouse Mov34 protein. Northern blot analysis revealed that p47 is expressed as a 1.3-kb mRNA in HeLa cells.