Investigation of the Effects of LisH Domain Proteins on the Drosophila Melanogaster Histone Cluster

Summer 2017

Andrew C. Lu : Molecular and Cell Biology

Donor: Pergo Fund
Mentor: Robert Tjian, Chiahao (Kevin) Tsui

Many tandemly repeated histone gene clusters exist in the Drosophila Melanogaster genome and are subjected to complex regulation during the cell cycle. However, the exact mechanism of this regulation remains elusive. Using a variant of the CRISPR/Cas9 system, we have developed a DNA-pulldown technique that, when coupled to mass-spectrometry, is capable of identifying bound proteins on a given promoter, enhancer, or any other regulatory DNA sequence. Applying this technique to the D. Melanogaster histone cluster, the pulldown samples interestingly showed an enrichment of a particular protein domain - LisH. Found in the Saccharomyces cerevisiae SIF2 protein, this LisH domain is thought to be responsible for the formation of dimer/tetramers and could be an integral part of the recruitment complex necessary for efficient and proper histone gene transcription. Indeed, one of the LisH proteins identified in the pulldown, Multi sex combs (Mxc), has been shown previously to be involved in the process of histone locus body formation. To address the functional importance of the other previously uncharacterized LisH domain proteins in the context of D. Melanogaster histone gene regulation, I will employ RNAi and overexpression screens in hopes of identifying novel components of the histone cluster transcription complex.

Thanks to the Pergo fund, working this summer really gave me an appreciation of working fulltime in lab. While working during the school year is important, it was difficult to dedicate as much time as I wanted to work because of school. Being able to take on a project by myself and work independently fulltime has been great and really affirmed my desires to work in academia and pursue basic science research. In addition, the SURF conference was an excellent forum for me to not only practice giving a formal scientific talk but it was also amazing to hear about all the work that all the other students did over the summer.