Date: Wednesday, 14 April 2021

Venue: Cheung Kung Hai Lecture Theatre 1, G/F, William M.W. Mong Block, Faculty of Medicine Building, 21 Sassoon Road, Pokfulam, Hong Kong [Mixed mode: Face-to-Face and Zoom]

Time: 5:00 p.m. - 6:00 p.m.

Zoom Link: https://hku.zoom.us/j/99210632004?pwd=anFEYzFIZVNORXVQNnkrMEIvdDZhZz09

Meeting ID: 992 1063 2004

Password: 495164

Time: 5:00 p.m.
Speaker: Dr. Chen Qiao
Primary Supervisor: Dr. YH Huang
Presentation Title: RNA velocity and representation learning for robust cellular transition estimation

RNA velocity is a promising technique for revealing transient cellular dynamics among a heterogeneous cell population, and for quantifying cellular transitions from single-cell transcriptome experiments. I will introduce the basics of RNA velocity from Manno (2018), how directed cellular transitions are inferred with estimated velocities, before proposing our work named VeloAE for more robust transition estimation. On various public experimental datasets, we show that VeloAE can not only accurately identify stimulation dynamics in time-series designs, but also effectively capture expected cellular differentiation in different biological systems. VeloAE, therefore, enhances the usefulness of RNA velocity for studying a wide range of biological processes.

Time: 5:30 p.m. 
Speaker: Dr. Ching Gee Choi
Primary Supervisor: Dr. SKY Ma
Presentation Title: Optimized SpCas9 variants identified via parallel profiling of barcoded combinatorial mutations
Abstract: Exploring how combinatorial mutations can be combined to optimize protein functions is important to guide protein engineering. Given the vast combinatorial space of changing multiple amino acids, identifying the top-performing variants from a large number of mutants might not be possible without a high-throughput gene assembly and screening strategy. To systematically analyze the combined effect of multiple mutations on the widely used Streptococcus pyogenes Cas9 (SpCas9) nuclease to optimize its genome-editing activity in human cells, we developed and applied the CombiSEAL strategy to generate a library of 948 barcoded combination mutants of SpCas9. Using this approach, editing activities of SpCas9 variants were accessed at multiple on- and off-target sites in a pool by high-throughput sequencing. We discovered a novel SpCas9 variant, named Opti-SpCas9, which has high editing efficiency, enhanced specificity and is useful for performing high-quality CRISPR screens.

Furthermore, genome-wide association studies of optic disc characteristics identified statistically significant association of a single nucleotide polymorphism (SNP) within PDZD2 with glaucoma endophenotypes. Interestingly, Pdzd2 mutant mice exhibited glaucoma characteristics including elevation in intraocular pressure and vertical cup- disc ratio, providing the first evidence that Pdzd2 is involved in the pathogenesis of glaucoma.

ALL ARE WELCOME

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