Inhibition of Translation and Progesterone-induced Maturation ofXenopusOocytes by Expressing the Amino-terminal Portion of the Eukaryotic Translation Initiation Factor 4G

2002 ◽  
Vol 66 (1) ◽  
pp. 185-187
Author(s):  
Motoaki WAKIYAMA ◽  
Kin-ichiro MIURA
Keyword(s):  
Translation Initiation ◽  
Translation Initiation Factor ◽  
Initiation Factor ◽  
Terminal Portion ◽  
Eukaryotic Translation Initiation Factor ◽  
Eukaryotic Translation ◽  
Amino Terminal ◽  
Eukaryotic Translation Initiation

scholarly journals A Novel Functional Human Eukaryotic Translation Initiation Factor 4G

1998 ◽  
Vol 18 (1) ◽  
pp. 334-342 ◽  
Author(s):  
Alessandra Gradi ◽  
Hiroaki Imataka ◽  
Yuri V. Svitkin ◽  
Eran Rom ◽  
Brian Raught ◽  
...  
Keyword(s):  
Translation Initiation ◽  
Amino Acid Level ◽  
Translation Initiation Factor ◽  
Host Protein ◽  
Initiation Factor ◽  
Eukaryotic Translation Initiation Factor ◽  
Eukaryotic Translation ◽  
Amino Terminal ◽  
Eukaryotic Translation Initiation ◽  
Picornavirus Infection

ABSTRACT Mammalian eukaryotic translation initiation factor 4F (eIF4F) is a cap-binding protein complex consisting of three subunits: eIF4E, eIF4A, and eIF4G. In yeast and plants, two related eIF4G species are encoded by two different genes. To date, however, only one functional eIF4G polypeptide, referred to here as eIF4GI, has been identified in mammals. Here we describe the discovery and functional characterization of a closely related homolog, referred to as eIF4GII. eIF4GI and eIF4GII share 46% identity at the amino acid level and possess an overall similarity of 56%. The homology is particularly high in certain regions of the central and carboxy portions, while the amino-terminal regions are more divergent. Far-Western analysis and coimmunoprecipitation experiments were used to demonstrate that eIF4GII directly interacts with eIF4E, eIF4A, and eIF3. eIF4GII, like eIF4GI, is also cleaved upon picornavirus infection. eIF4GII restores cap-dependent translation in a reticulocyte lysate which had been pretreated with rhinovirus 2A to cleave endogenous eIF4G. Finally, eIF4GII exists as a complex with eIF4E in HeLa cells, because eIF4GII and eIF4E can be purified together by cap affinity chromatography. Taken together, our findings indicate that eIF4GII is a functional homolog of eIF4GI. These results may have important implications for the understanding of the mechanism of shutoff of host protein synthesis following picornavirus infection.

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