School of Biomedical Sciences cordially invites you to join the following Post-doctoral Fellow (PDF) Seminar:

Date: 22 April 2025 (Tuesday)
Time: 4:00 pm – 5:00 pm
Venue: Lecture Theatre 1, G/F, William M.W Mong Block, 21 Sassoon Road
Host: Dr. Haifeng Fu

Light refreshments will be served. Please register via the below link by 21 April 2025 (Monday).
Registration: https://hku.au1.qualtrics.com/jfe/form/SV_eff9OdRTYRXijlk

Nuclear PRMT5 promotes HBV transcriptions by affecting the histone modifications of HBV genome
Dr. Tao Cheng (Post-doctoral Fellow)
[Supervisor: Professor Dong-yan Jin]

Hepatitis B can cause a chronic infection that eventually results in cirrhosis and liver cancer, thus threatening a major global health. Understanding how HBV transcriptions are regulated could contribute to finding the potential targets of the novel therapy of HBV infection. Protein arginine N-methyltransferase 5 (PRMT5) is an enzyme that symmetrically dimethylates histones linked to a range of transcriptional regulatory events. However, there is a controversy about the function of  PRMT5 in the HBV life cycle. In this study, our data suggested that Nuclear PRMT5 promotes HBV transcriptions. To further investigate the molecular mechanisms, we observed that HBV help to transport PRMT from cell cytoplasm to cell nucleus and that nuclear PRMT5 could affect the histone modifications of HBV genome. In conclusion, our findings about the functions of PRMT5 in HBV transcriptions may indicate that PRMT5 is a potential target for HBV therapy.

Investigation on structure and catalytic mechanism of Israeli acute paralysis virus (IAPV) 3D polymerase
Dr. Xiang Fang (Post-doctoral Fellow)
[Supervisor: Professor Tao Ni]

The Dicistroviridae is a virus family that includes many insect pathogens. These viruses contain a positive-sense RNA genome that is replicated by the virally encoded RNA-dependent RNA polymerase (RdRP) also named 3D^pol. Compared with the Picornaviridae RdRPs such as poliovirus (PV) 3D^pol, the Dicistroviridae representative Israeli acute paralysis virus (IAPV) 3D^pol has an additional N-terminal extension (NE) region that is about 40-residue in length. To date, both the structure and catalytic mechanism of the Dicistroviridae RdRP have remain elusive. Here we resolved crystal structures of two truncated forms of IAPV 3D^pol, namely Δ85 and Δ40, both missing the NE region, and the 3D^pol protein in these structures exhibited three conformational states. The palm and thumb domains of these IAPV 3D^pol structures are largely consistent with those of the PV 3D^pol structures. However, in all structures, the RdRP fingers domain is partially disordered, while different conformations of RdRP substructures and interactions between them are also present. These experimental data on one hand show intrinsic conformational variances of RdRP substructures, and on the other hand suggest possible contribution of the NE region in proper RdRP folding in IAPV.

All are welcome.