Amino acid sequence of the human protein synthesis initiation factor eIF-4 gamma.
Eukaryotic protein synthesis initiation factor (eIF) 4 gamma, also known as p220, is a component of the protein complex eIF-4, which is involved in the recognition of the mRNA cap, ATP-dependent unwinding of 5'-terminal secondary structure and recruitment of mRNA to the ribosome. Peptide sequence data from rabbit reticulocyte eIF-4 gamma was used to synthesize oligonucleotide probes and polymerase chain reaction primers. These were used to screen lambda-cDNA libraries from rabbit and human brain, yielding a partial rabbit and a complete human cDNA sequence of 5.1 kilobases. Northern blot and primer extension analysis indicated that the cDNA sequence was complete. To confirm that the cDNA represented that of eIF-4 gamma, three peptides were synthesized based on cDNA sequences and used to produce anti-peptide antibodies. The antibodies specifically recognized intact eIF-4 gamma and its cleavage products following poliovirus infection. The eIF-4 gamma mRNA contains AUG codons at nucleotides 6, 67, 90, 165, and 369, but only the last is followed by a long open reading frame. The eIF-4 gamma polypeptide is 154 kDa (1396 amino acid residues) and contains sequence motifs of potential interest: a sequence (AGLGPR) that is similar to the substrate recognition sequence of protease 2A from rhinovirus serotype 14, five PEST regions with scores greater than 10, which are characteristic of rapidly degraded proteins, stretches of polyglutamic acid, and numerous potential phosphorylation sites.
Yan
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Department of Biochemistry, University of Kentucky Medical Center, Lexington 40536.
Rychlik
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Etchison
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Rhoads
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D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D001921:Brain / Q000502:physiology*; D003001:Cloning, Molecular; D004247:DNA / Q000235:genetics / Q000302:isolation & purification; D039562:Eukaryotic Initiation Factor-4F; D015723:Gene Library; D006031:Glycosylation; D006801:Humans; D046911:Macromolecular Substances; D008969:Molecular Sequence Data; D015345:Oligonucleotide Probes; D016366:Open Reading Frames; D010446:Peptide Fragments / Q000235:genetics* / Q000378:metabolism; D010448:Peptide Initiation Factors / Q000235:genetics* / Q000378:metabolism; D010766:Phosphorylation; D012315:RNA Caps / Q000378:metabolism; D011817:Rabbits; D015183:Restriction Mapping
D039562:Eukaryotic Initiation Factor-4F; D046911:Macromolecular Substances; D015345:Oligonucleotide Probes; D010446:Peptide Fragments; D010448:Peptide Initiation Factors; D012315:RNA Caps; C069883:initiation factor 4F component p220; D004247:DNA