Biophysical Society Thematic Meeting| Santa Cruz 2018

Genome Biophysics: Integrating Genomics and Biophysics to Understand Structural and Functional Aspects of Genomes

Poster Abstracts

2-POS Board 2 Systematic Study of Nucleosome-Depleting Factors in Budding Yeast Lu Bai . Pennsylvania State University, University Park, USA.

Nucleosomes present a barrier for the binding of most transcription factors (TFs). However, special TFs known as nucleosome-depleting factors (NDFs) can access embedded sites and cause nucleosome depletion. Here, we developed a novel high-throughput method in yeast to identify NDFs among 104 TFs and systematically characterized the impact of orientation, affinity, location, and copy number of their binding motifs on nucleosome depletion level. Using this assay, we identified ~20 new NDF motifs and divided the nuclear TFs into three groups with strong, weak, and no nucleosome-depleting activities. Further studies revealed that tight DNA binding is the key property that underlies strong NDF activity, and this activity has cell-cycle dependence. These observations lead to a model where NDFs function by binding to transiently exposed motifs during DNA replication and preventing nucleosome formation. Overall, our study presents a new framework to functionally characterize NDFs and elucidate the mechanism of nucleosome invasion.

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