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Tian Xia

Tian Xia

Preferred Name:



B.S. Biochemistry and Molecular Biology, Minor in Psychology

Class of 2021

Pennsylvania State University, State College PA 

From: Shenzhen, China

Joined David Lab: January 2022

Outside of the lab: I play Guzheng, a traditional Chinese instrument; I love baking cakes and cooking; I also enjoy traveling and exploring foods.

Research in David Lab:

As a consequence of cellular respiration, reactive oxygen species would form and pose threats to the integrity of the genome. A common product of oxidized guanine is 8-oxo-7,8-dihydroguanine (8-oxoG), in which the syn conformation promotes a Hoogsteen pairing with adenine. Misincorporation of adenine instead of cytosine and subsequent replication would lead to a G:C to A:T mutation. The accumulation of mutation in the Adenomatous Polyposis Coli (APC) gene is correlated to the early onset of colorectal cancer (CRC). As a defense against the mutation, MUTYH, a base excision repair (BER) enzyme, cleaves the adenine paired opposite to 8-oxoG. Germ-line mutations in MUTYH have been linked to an autosomal recessive form of familial CRC termed MUTYH-associated Polyposis (MAP). It is crucial to understand the structure and mechanism of MUTYH to predict and prevent disease. I’m interested in elucidating the structure and function of MUTYH through cellular repair assay. To be more specific, I generate MUTYH mutants by site-directed mutagenesis and measure the OG:A repair percentage by mutant cell lines using a reporter assay. The result would provide support to our proposed MUTYH structure. 


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Dr. Sheila S. David

Department of Chemistry
One Shields Ave.
Davis, CA 95616