UROP Proceedings 2020-21

School of Science Division of Life Science 16 Molecular Mechanisms Regulating Secretion of Sonic Hedgehog Supervisor: GUO Yusong / LIFS Student: AGRAWAL Diya / BCB Course: UROP1100, Fall This report explored the trafficking of Frizzled6 protein using the RUSH system. Frizzled6 (Fzd6) being a transmembrane protein localised in the plasma membrane follow the secretory transport pathway. RUSH (Retention Using Selective Hooks) provides a mechanism to regulate the trafficking by retaining proteins of interest in desired organelles and releasing them upon treatment. In this report, RUSH-Fzd6 DNA construct is prepared by molecular cloning and transfected into HeLa cells. Fzd6 is tethered to Enhanced Green Fluorescence Protein (EGFP) as a reporter. Since the experiment is currently in progress, the paper establishes the expected outcomes of visualisation pattern of the protein under fluorescence microscope where initially, reporter and protein of interest are retained in ER and upon biotin treatment, they get exported from ER becoming visible in Golgi apparatus and subsequent organelles along the secretory pathway. Understanding Neuronal and Molecular Mechanisms Defining Behavioral Individuality Supervisor: HIRANO Yukinori / LIFS Student: CHO King Yi / BCB Course: UROP1000, Summer Behaviors are drastically shaped by experiences, while some aversive experience may induce behavioral alterations that can be retained for a long period. The central question is: how aversive experience is integrated into neural circuits affecting animal's behavioral repertoire? In current stage, we applied electric shock to 2202u wild type Drosophila and quantified their preference for wide or narrow arms using optimum 2-arms arenas after being shocked, as well as the retention duration of such preference. Our results show that flies generally shift towards anxiety-like behavioral phenotypes upon electric shock, which can be manifested as displaying a stronger disfavor towards narrower space or a stronger preference towards wide space. This claustrophobic-like preference could retain for at least 2 hours after shock. Biochemical Characterization of Histone Variants and Post-translationally Modified Nucleosomes Supervisor: ISHIBASHI Toyotaka / LIFS Student: TSUI Long Wai / BIBU Course: UROP1100, Fall Histones are evolutionarily highly conservative proteins that bind DNA in nucleus to form dense nucleosomes. A functional histone complex is an octamer, consisting two of each subunits H2A, H2B, H3 and H4. Variants of these subunits may deliver functions distinct from canonical histones. H2BFW is a variant of histone subunit H2B. Clinical data shows that mutation in H2BFW in male patients correlates with infertility. It is suspected that H2BFW functions to destabilize nucleosome in spermatogenesis, while the mutant form fails to do so. This study looks into the stability of H2BFW nucleosomes, and compare it to that of H2BFWmutant and canonical nucleosomes, using biochemical and biophysical techniques. This UROP report will be divided into three parts. In the first part, I will report on the work and results in the H2BFW study. In the second part, I will include progress on histone variant mouse H2A.P characterization. In the final part, I will give a brief reflection on my experience and discuss future research directions.

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