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Tutor in Biochemical Sciences

Yang Shi

Tutor in Biochemical Sciences


Epigenetics refers to changes in gene expression that do not involve changes in DNA sequences. A distinguishing feature of epigenetic regulation is the ability to offer both stability and flexibility as mechanisms for controlling gene expression, contrary to genetic regulation, which is irreversible. Consequently, epigenetic regulation likely functions as a dynamic conduit for interaction between a cell/organism and its surrounding environment.

A major component of epigenetic regulation occurs in chromatin, where covalent and non-covalent modifications can lead to heritable changes in gene expression. The basic unit of chromatin is the nucleosome, which is composed of 146 base pairs of DNA that wrap around a histone octamer, including two copies of histones H2A, H2B, H3 or H4.  Both DNA and histone are chemically modified. The cytosine of DNA can be methylated and hydroxymethylated, and CpG methylation has been shown to play a critical role in epigenetic regulation. Histones are modified extensively at N-terminal tails via phosphorylation, acetylation, methylation, and ubiquitination.

The Shi Lab is interested in studying histone methylation as a steady yet revocable process, supported by Yang Shi’s research and discovery of histone demethylases, as well as other components of epigenetic regulatory mechanisms.