School of Science Division of Life Science 24 Targeting Mitotic Regulators in Cancer Cells for Potential Treatment Supervisor: POON Randy Yat Choi / LIFS Student: CHONG Man Yan / IRE Course: UROP1000, Summer Chinese hamster ovary (CHO) cells are an important host for therapeutic protein production. However, its potential as a gene knockout system for characterizing the role of cell cycle control genes have not been developed. Our laboratory has recently developed an approach for constructing conditional gene silencing cell lines in HeLa cells by integrating the transcriptional control of the tetracycline-controlled promoter system and the post-translational regulation of auxin-inducible degron (AID). In this study, we investigated the possibility of constructing a similar system in CHO cell lines by transfecting a plant F-box protein (AFB2) and tetracycline-controlled transcriptional activator (tTA) genes into CHO-AA8 through the Sleeping Beauty transposon system. Moreover, we tested the possibility to arrest CHO cells in G1 phase with the drug lovastatin. Targeting Mitotic Regulators in Cancer Cells for Potential Treatment Supervisor: POON Randy Yat Choi / LIFS Student: SINGHOF Michelle / BCB Course: UROP1100, Spring Cell wounding refers to plasma membrane damage. Plasma membrane repair is integral to the survival of cells after wounding and involves a multi-step process. Ca2+-influx triggers the exocytosis of vesicles such as lysosomes. The extracellular release of lysosomal sphingomyelinase then triggers caveolar-endocytosis of the plasma membrane lesions. This process is distinct from conventional clathrin-mediated endocytosis. Cell wounding is especially common in mechanically active tissues such as skeletal muscle, and plasma membrane repair defects at any of these stages have been linked to a number of myopathies. Identification of actors in plasma membrane repair thus may be key to finding targets for new therapies. Targeting Mitotic Regulators in Cancer Cells for Potential Treatment Supervisor: POON Randy Yat Choi / LIFS Student: SUN Run / BCB Course: UROP1100, Fall Apoptosis is the process of programmed cell death which is critical for cells to survive. Normal cells use this mechanism to clean the body of cells that are irreparable to prevent cancer cells. However, abnormal cells such as cancer cells have deficiency in this function and may grow without control. So, it is indispensable to study the mechanism behind the process of apoptosis and unveil the essential genes related to it. In this study, we try to uncover the relationship between some relevant genes and MARCH5, a known E3 ubiquitinprotein ligase localized in the mitochondrial outer membrane, and the pathway of how the deficiency of MARCH5 can lead to mitotic cell death in cancer cells. The novel gene UBE2J2 is reported to have high correlation with MARCH5. We found that UBE2J2 shows discrepancy in different tissues. However, the knockout of UBE2J2 was not very successful in the first part of the experiment. Also, direct interaction between MARCH5 and UBE2J2 was also not shown via immunoprecipitation.