Date: 12 May 2023 (Fri)

Time: 5:00 p.m. - 6:00 p.m.

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

5:00 p.m.

Presenter: Miss Xinning HU (MPhil candidate)
Primary Supervisor: Prof. Pengtao LIU
Presentation Title: ALKBH1-mediated 6mA DNA methylation regulates cell fate determination via TGFβ signalling pathway
Abstract: DNA methylation, including the prevailing 5-methylcytosine (5mC) modification, is a fundamental epigenetic mechanism that regulates various biological functions, including cancer, neurodegeneration, and embryogenesis. In addition to 5mC, the 6-methyladenine (6mA) DNA modification has recently been identified in eukaryotes, including mammalian stem cells, but its role in gene regulation and cell fate determination remains poorly understood. In 2016, the first discovery of 6mA in mammalian stem cells was reported, which sparked interest in elucidating its function. In this study, we used CRISPR-Cas9 gene editing to knock out the putative demethylase of 6mA DNA modification, ALKBH1, in human expanded potential stem cells (hEPSCs). The KO of ALKBH1 led to a significant increase in 6mA levels in hEPSCs, resulting in the downregulation and hypermethylation of TGFβ-related genes. This, in turn, affected cell fate determination, highlighting the importance of understanding the role of 6mA in embryonic development.

5:30 p.m.

Presenter: Mr. Chi Kit CHENG (MPhil candidate)
Primary Supervisor: Dr. Sung Chul KWON
Presentation Title: Cytosolic crRNA for Cas13 systems
Abstract: Among the diverse CRISPR/Cas systems, the type VI Cas13 family is specialised at targeting RNA instead of DNA. In recent years, many Cas13 subfamilies have been discovered and engineered for various RNA editing applications. However, efficiencies of such applications remain limited. Here we show that the RNA targeting efficiency of multiple Cas13 systems is significantly enhanced when the Cas13 proteins share the same subcellular localisation with corresponding crRNA in the cytosol. Such increase in efficiencies is observed for both RNA cleavage and RNA editing, with catalytically active Cas13 proteins and inactive versions respectively. Our results suggest that the biogenesis of cytosolic crRNA could be the key to unlock the full potential of Cas13 proteins. Further understanding of the crRNA biogenesis mechanism, together with development of new RNA-editing domains, may provide new insights to establish better RNA editing tools for both research and clinical applications.

ALL ARE WELCOME

Should you have any enquiries, please feel free to contact Miss Cynthia Cheung at 3917 9748.