Title: Directed evolution of adenosine deaminases for epigenetic profiling and gene editing
Abstract: N6-methyladenosine (m6A), the most prevalent internal mRNA modification in higher eukaryotes, depicts a regulatory network extensively involved in the mRNA life cycle. To elucidate the multitude of functions served by m6A, we developed evolved TadA-assisted N6-methyladenine sequencing (eTAM-seq), an enzyme-assisted sequencing technology that detects and quantifies m6A by global adenosine deamination. With eTAM-seq, we profiled m6A in the transcriptomes of cell lines and mouse tissues. I will discuss development, applications, and current limitations of eTAM-seq.
For the second half of my talk, I will present our recent progress on directed evolution of an adenine base editor (ABE) with increased context compatibility. Existing ABEs function most effectively when the target A is in a TA context. We report directed evolution of TadA8r, a new TadA variant that extends potent deoxyadenosine deamination to RA (R = A or G). ABE8r outperforms existing editors in correcting 41.9% of 9,407 disease-associated G:C-to-A:T transitions in the human genome, and shows a controlled off-target profile. I will present the development and applications of TadA8r in gene editing. I will also discuss how directed evolution may be harnessed to shape context compatibility and specificity.
Bio: Weixin Tang received her B.S. in Chemistry and Biology from Tsinghua University and her Ph.D. in Chemistry from the University of Illinois, Urbana-Champaign. She was a Jane Coffin Childs Memorial postdoctoral fellow at the Broad Institute of MIT and Harvard prior to joining the Chemistry Department at the University of Chicago as a Neubauer Family Assistant Professor in 2019. The Tang Lab works towards a comprehensive toolbox for precise manipulation of the human genome, and for detecting epigenetic and epitranscriptomic modifications at high resolution.
Keywords: protein engineering, genomics, gene editing
Faculty Host: Prof. Tina Wang