The HBx and HBc of hepatitis B virus can influence Id1 and Id3 by reducing their transcription and stability

• Published in: Virus research 2020-07, Vol.284, p.197973-197973, Article 197973
• Main Authors: Xia, Lulu, Wang, Shilie, Zhang, Hongpeng, Yang, Yuan, Wei, Jie, Shi, Yueyuan, Zou, Chunhong, Liu, Junye, Luo, Miao, Huang, Ailong, Wang, Deqiang
• Format: Article
• Language: English
• Subjects: HBc; HBV; HBx; Id1; Id3
• ISSN: 0168-1702; 1872-7492
• DOI: 10.1016/j.virusres.2020.197973

•HBV inhibited the expression of Id1 and Id3 by HBc and HBx.•HBc suppressed the expression of Id1 and Id3 by BMP/Smad signaling pathway.•HBx interacted with both Id1 and Id3 at residues 112-136 of HBx.•HBx down-modulated Id1 and Id3 proteins by accelerating their degradation. Hepatitis B virus (HBV) infection is closely related with the occurrence and development of hepatocellular carcinoma (HCC), in which Hepatitis B virus x protein (HBx) and core protein (HBc) play crucial roles. Additionally, inhibitors of differentiation (Id) proteins exhibited significant correlation with liver cancer development. Here, we identified that HBV dramatically inhibited the expression of Id1 and Id3 in both protein and transcriptional levels for the first time, whereas there was little effect of the virus on Id2. Additionally, two HBV coded protein, HBc and HBx, could reduce the expression of Id1 and Id3 distinctly, whereas the other two viral proteins, HBs and HBp were unable to affect Id1 and Id3 proteins. Both the activity inhibitors and activators further confirmed that HBc inhibited the expression of Id1 and Id3 by BMP/Smad signaling pathway. HBx could interact with both Id1 and Id3 at residues 112-136 of HBx protein, and it could inhibit the two Id proteins by accelerating their degradation. This is the first report about HBc and HBx regulating Id1 and Id3, whereas the detailed mechanism associated with above needed further experiments to clarify.