UROP Proceedings 2020-21

School of Science Division of Life Science 17 Biochemical Characterization of Histone Variants and Post-translationally Modified Nucleosomes Supervisor: ISHIBASHI Toyotaka / LIFS Student: TSUI Long Wai / BIBU Course: UROP2100, Spring H2A.P is a testis-specific histone variant of H2A that is not well-understood. Although H2A.P is predicted to have a secondary structure that resembles canonical H2A, we found that human H2A.P localizes in the cytosol instead of the nucleus, while mouse H2A.P is more enriched in the cytosol than the nucleus in mammalian cells. Fluorescence recovery after photobleaching assay showed that human H2A.P is not bound to a stable structure in the cytosol. These interesting observations suggested that H2A.P probably does not bind DNA and form nucleosomes as typical histones do, and has distinct functions from canonical H2A. Domain-swap assay revealed that mouse H2A.P N-terminal and the histone-fold domain together are sufficient to exclude H2A from the nucleus and mouse H2A.P C-terminal may contribute to nucleus localization. Investigating the Effects of MEF2D on Transcription Dynamics at a Single-Molecule Level Supervisor: ISHIBASHI Toyotaka / LIFS Student: LEONG Kin Nam / BCB Course: UROP1100, Fall Previous research has shown that MEF2D (Myocyte-specific enhancer factor 2D) protein enhances polymerase transcription activity, however, a quantitative measurement of its effects has not been done. This project aims to investigate the quantitative effects of MEF2D on the dynamics of RNA polymerase transcription at a single molecule level, using optical tweezers. Results are unavailable at the time this report was written but has significant progress since the last progress report. This report focuses on the recap of the project, changes made to the experiment system, improvements that enabled progress and the current stage of the experiment.

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