School of Science Division of Life Science 38 Study of Blood Cell Development using Zebrafish Model Supervisor: WEN Zilong / LIFS Student: LI Yunbo / BCB Course: UROP3100, Fall Metaphocytes are non-hematopoiesis-derived myeloid-like cell populations found in zebrafish epidermis, gill, and intestine. How metaphocytes adopt a myeloid-like cell fate becomes an intriguing question. To explore metaphocyte development, we investigated the maintenance of metaphocytes by studying metaphocyte progenitorcells (MPCs) recently found in zebrafish epidermis. MPCs are small and round cells, which are different from the ramified morphology of metaphocytes. RNA sequencing analysis further showed that MPCs do not express macrophage marker mpeg1 but express metaphocyte marker mstf1 and some proliferation-related genes. To investigate MPCs, we selected a candidate MPC marker gene, anxa2al, and synthesized antisense anxa2al in situ hybridization probe to test its labeling specificity. The double transgenic line Tg(mstf1:CreER;mpeg1:LoxP-DsRedx-LoxP-GFP) was also generated for MPC-metaphocyte lineage tracing study. Study of Blood Cell Development using Zebrafish Model Supervisor: WEN Zilong / LIFS Student: FAN Yining / BCB Course: UROP2100, Spring In order to find out molecular mechanisms of cerebral cavernoma malformation (CCM) associated with MAP3K3-I441M, a recently identified mutation, we generated several zebrafish disease models. Among these models, Bacteria Artificial Chromosomes (BACs) transgenic lines are necessary because it is able to mimic the endogenous expression patterns of the MAP3K3 gene. This semester we tried to generate BACtransgenic lines and all cassettes (including itol2 and target cassette) have already been electroporated into DH10B E.coli. Further experiments for selecting and confirming correct colonies will be carried out in the future. Study of Blood Cell Development using Zebrafish Model Supervisor: WEN Zilong / LIFS Student: LI Zhuying / SSCI Course: UROP1100, Summer Aggregation of TDP-43 in neurons has been a pathological hallmark of amyotrophic lateral sclerosis (ALS) and frontotemporal lobar degeneration (FTLD). To study the role of TDP-43 aggregation in vivo, we generated transgenic zebrafish overexpressing either wild-type TDP-43z or a mutated form with a M337V substitution. These overexpression lines showed neural abnormalities, including cytoplasmic mislocalization of TDP-43z and fragmentation of TDP-43z overexpressing neurons. Furthermore, we observed microglia uptaking the TDP-43z positive debris. Altogether, we established TDP-43 overexpression models in zebrafish which will serve as a powerful tool to study the underlying mechanisms of neurodegenerative diseases and neuron-immune cell interactions in pathological conditions.