Regulation mechanism of p27 IRES translation activity under large HBV surface protein-induced endoplasmic reticulum stress
GUO Yixiao
SHAO Jie
WEI Ding
CHEN Zhinan
BIAN Huijie
Abstract：Objective To investigate the activity changes of internal ribosome entry site(IRES)in tumor suppressor gene p27 5'UTR and its regulatory mechanism under endoplasmic reticulum stress induced by large HBV surface protein(LHB).Methods Dual-luciferase reporter plasmid was constructed,and dual-luciferase reporter assay was used to detect the activity of IRES in p27 5'UTR.qRT-PCR and Western blotting were used to detect the expression levels of unfolded protein response-related molecules induced by LHB.RNA pull-down,mass spectrometry and immunoprecipitation were used to screen and verify the potential proteins that bound to p27 5'UTR.The knock-down cell models of PCBP2 and ANXA2 were established with siRNA transfection,and changes in the translation activity of p27 IRES in PCBP2 and ANXA2 knock-down cells were detected by dual-luciferase reporter assay.Results A dual-luciferase reporter plasmid was constructed to detect the activity of p27 IRES.LHB could induce endoplasmic reticulum stress and significantly increased the translation activity of p27 IRES(P＜0.01).Overexpression of LHB activated PERK pathway and increased the phosphorylation of eIF2α.The phosphorylation level of RERK and eIF2α was decreased by using the specific PERK pathway inhibitor GSK2606414,and the IRES translation activity of p27 5'UTR was significantly decreased(P＜0.01,P＜0.05).Meanwhile,phosphatase inhibitor Sal003 significantly increased the phosphorylation level of eIF2α,which further enhanced the activity of p27 IRES(P＜0.01,P＜0.05).Finally,we found that PCBP2 and ANXA2 as potential IRES trans-acting factors,played a positive role in enhancing the activity of p27 IRES.Conclusion LHB-induced endoplasmic reticulum stress enhances the translation activity of p27 IRES through eIF2α phosphorylation.IRES trans-acting factors PCBP2 and ANXA2 positively regulate the translation activity of p27 IRES.
Keywords：large HBV surface proteinp27 5'UTRendoplasmic reticulum stressinternal ribosome entry sitesIRES trans-acting factor
Publication Date：2024-07-28
Online Publishing Date：2026-08-26(First online date of this platform, not the publication date of the document)
Pages：8( 732-739 )