Start main content

May 10, 2023

PDF Seminar (2023-05-10)

Date: 10 May 2023 (Wednesday)

Time: 5:00 p.m. - 6:00 p.m.

Venue: Lecture Theatre 1, G/F, William M.W. Mong Block, 21 Sassoon Road


5:00 p.m.

Speaker: Dr. Tao Cheng (Post-doctoral Fellow)
Primary Supervisor: Professor Dong-Yan Jin
Presentation Title: The function of chromatin architectural protein CTCF in HBV transcription
Abstract: Hepatitis B virus (HBV) is a small DNA virus with an envelope, currently still posing a great threat to human health. Its genome is a minichromosome in the nucleus decorated with histones and other host factors. It is still not well elucidated as to how HBV transcription is regulated. CCCTC-binding factor (CTCF) is a multi-functional host chromatin architectural protein that regulates gene expression.However, the roles of CTCF in HBV transcription remain obscure.   Knocking down CTCF expression repressed HBV transcription, whereas overexpression of CTCF facilitated HBV transcription. In addition, truncated CTCF NZ without C-terminal domain of CTCF can rescued the phenotypes caused by knocking down CTCF expression, and overexpressing only the CTCF N-terminal domain exhibited an inhibitory effect on HBV transcription,suggesting that its N-terminal domain is required for CTCF promotion of HBV transcription. knocking down CTCF triggered less HBx, less WDR5, and less RNA polymerase II occupancy to the HBV genome, and also triggered less H3K4Me3 and more H3K9Me3 occupancy to the HBV genome. In conclusion, CTCF promoted HBV transcription. 


5:30 p.m. 

Speaker: Dr. Zi-Wei Ye (Research Assistant Professor)
Primary Supervisor: Professor Dong-Yan Jin
Presentation Title: Combinational attenuation of NSP16 and ORF3a for generating live attenuated SARS-CoV-2 vaccines
Abstract: Live attenuated vaccines possess the advantages of providing mucosal immunity against that existing SARS-CoV-2 vaccines fail to induce. We previously generated and reported a candidate live attenuated vaccine strain of SARS-CoV-2 with 2¢-O-methyltransferase catalytically inactivated by the nsp16 D130A mutation, which was designated as d16. Though a single dose of intranasal vaccination with d16 conferred mucosal and sterilizing immunity in both upper and lower respiratory tracts of animals, concerns of virulence rebound and suboptimal inflammatory control remains after d16 vaccination and natural infection. We further introduced ORF3a deletions into d16 (designated as d16Δ3a), which was observed to be more attenuated and thus safer than d16. Intranasal vaccination of d16Δ3a robustly stimulated humoral and cell-mediated immune responses, conferring protection against SARS-CoV-2 variants (Delta and Omicron) challenge in animals. Notably, secretory immunoglobulin A was detectable in blood and nasal wash of vaccinated hamsters, indicating a robust introduction if mucosal immunity. Collectively, our work suggests dual attenuation of SARS-CoV-2 2¢-O-methyltransferase and ORF3a for rapid generating safe and effective live attenuated vaccines.



Should you have any enquiries, please feel free to contact Miss Angela Wong at 3917 9216.