Structure of cDNAs encoding human eukaryotic initiation factor 3 subunits. Possible roles in RNA binding and macromolecular assembly.
The mammalian translation initiation factor 3 (eIF3), is a multiprotein complex of approximately 600 kDa that binds to the 40 S ribosome and promotes the binding of methionyl-tRNAi and mRNA. cDNAs encoding 5 of the 10 subunits, namely eIF3-p170, -p116, -p110, -p48, and -p36, have been isolated previously. Here we ... report the cloning and characterization of human cDNAs encoding the major RNA binding subunit, eIF3-p66, and two additional subunits, eIF3-p47 and eIF3-p40. Each of these proteins is present in immunoprecipitates formed with affinity-purified anti-eIF3-p170 antibodies. Human eIF3-p66 shares 64% sequence identity with a hypothetical Caenorhabditis elegans protein, presumably the p66 homolog. Deletion analyses of recombinant derivatives of eIF3-p66 show that the RNA-binding domain lies within an N-terminal 71-amino acid region rich in lysine and arginine. The N-terminal regions of human eIF3-p40 and eIF3-p47 are related to each other and to 17 other eukaryotic proteins, including murine Mov-34, a subunit of the 26 S proteasome. Phylogenetic analyses of the 19 related protein sequences, called the Mov-34 family, distinguish five major subgroups, where eIF3-p40, eIF3-p47, and Mov-34 are each found in a different subgroup. The subunit composition of eIF3 appears to be highly conserved in Drosophila melanogaster, C. elegans, and Arabidopsis thaliana, whereas only 5 homologs of the 10 subunits of mammalian eIF3 are encoded in S. cerevisiae.
Mesh Terms:
Amino Acid Sequence, Animals, Base Sequence, Caenorhabditis elegans, Cloning, Molecular, Conserved Sequence, DNA, Complementary, DNA-Binding Proteins, Eukaryotic Initiation Factor-3, Evolution, Molecular, Female, Hela Cells, Humans, Macromolecular Substances, Molecular Sequence Data, Molecular Weight, Multiprotein Complexes, Organ Specificity, Peptide Fragments, Peptide Initiation Factors, Phylogeny, Polymerase Chain Reaction, Pregnancy, Protein Biosynthesis, RNA, Messenger, Rabbits, Reticulocytes, Sequence Alignment, Sequence Homology, Amino Acid, Transcription, Genetic
Amino Acid Sequence, Animals, Base Sequence, Caenorhabditis elegans, Cloning, Molecular, Conserved Sequence, DNA, Complementary, DNA-Binding Proteins, Eukaryotic Initiation Factor-3, Evolution, Molecular, Female, Hela Cells, Humans, Macromolecular Substances, Molecular Sequence Data, Molecular Weight, Multiprotein Complexes, Organ Specificity, Peptide Fragments, Peptide Initiation Factors, Phylogeny, Polymerase Chain Reaction, Pregnancy, Protein Biosynthesis, RNA, Messenger, Rabbits, Reticulocytes, Sequence Alignment, Sequence Homology, Amino Acid, Transcription, Genetic
J. Biol. Chem.
Date: Oct. 24, 1997
PubMed ID: 9341143
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