2001年1月16日 · The question of whether translation initiation factor eIF4E and the complete eIF4G polypeptide are required for initiation dependent on the IRES (internal ribosome entry site) of hepatitis A virus (HAV) has been examined using in vitro translation in standard and eIF4G-depleted rabbit reticulocyte lysates.

2019年8月9日 · Moreover, a recent biochemical and biophysical study suggested that polio virus (PV) and HAV IRES domains may share a common mechanism of binding and utilizing translation initiation factors such...

Cleavage of eIF4G, a protein scaffold of eIF4F, by sequence specific proteases 2A protease or L-protease, will result in highly inhibited HAV IRES activity. These proteases are encoded by other members of the picornaviridae family.

The HAV IRES can bind both intact eIF4G and the proteolytic C-terminal fragment with similar affinities. The C-terminal cleavage product of eIF4G with its associated eIF4A and eIF3 (Cp c-eIF4A-eIF3) is sufficient to drive type I and type II IRES activity.

The question of whether translation initiation factor eIF4E and the complete eIF4G polypeptide are required for initiation dependent on the IRES (internal ribosome entry site) of hepatitis A virus (HAV) has been examined using in vitro translation in …

1997年10月13日 · Translation inhibition correlated closely with the extent of cleavage of the one identified common cellular target for the 2A and Lb proteinases, eukaryotic initiation factor (eIF) 4G, a component of the eIF4F cap-binding protein complex. Total rescue of HAV IRES activity was possible if purified eIF4F was added to translation extracts.

2017年9月5日 · Here we demonstrate that eIF4E regulates HAV IRES-mediated translation by two distinct mechanisms. First, eIF4E binding to eIF4G generates a high-affinity binding conformation of the eIF4F complex for the IRES. Second, eIF4E binding to eIF4G strongly stimulates the rate of duplex unwinding by eIF4A on the IRES.

The hepatitis A virus (HAV) internal ribosome entry segment (IRES) is unique among the picornavirus IRESs in that it is inactive in the presence of either the entero- and rhinovirus 2A or aphthovirus Lb proteinases. Since these proteinases both cleave eukaryotic initiation factor 4G (eIF4G) and HAV …

These results suggest that HAV IRES-mediated translation can be stimulated by a poly(A) tail in Huh-7 cell as well as in HeLa cell extracts. The poly(A) tail interacts with PABP, which mediates efficient translation by circularization of HAV IRES mRNA via an IRES-eIF4G-PABP-poly(A) interaction (Michel et al., 2001). Our results show that HAV ...

2012年12月18日 · Our present findings clearly demonstrate that protein synthesis directed by HAV IRES can occur when eIF4G has been cleaved and after inactivation of eIF2. Therefore, translation directed by HAV IRES without intact eIF4G and active eIF2 is similar to that observed with other picornavirus IRESs.