Sarah Nemsick (HANSEN LAB)

Characterizing Bidirectional Promoter Transcriptional Dynamics Using Live-cell Nascent RNA Imaging

Approximately 11% of human genes are under the control of a bidirectional promoter (BDP), defined as two divergent genes with <1kb between their transcription start sites. Despite an enrichment for essential and oncogenic genes, the regulatory function of BDPs remains largely unknown. Here we aim to study BDP transcriptional dynamics using two-color live-cell nascent RNA imaging of 12+ human bidirectional promoters. This will provide insight into broad BDP dynamics and serve as the basis for in-depth mechanistic study of BDP regulation.

Domenic Narducci (HANSEN LAB)

Putative Looping Factor ZFP143 is an Essential Transcriptional Regulator with No Looping Function

Interactions between enhancers and promoters are central to gene regulation in mammals, yet the protein regulators of these interactions remain largely undetermined. The zinc finger transcription factor ZFP143 has been strongly implicated as a regulator of chromatin interactions, functioning either with or without CTCF. However, ZFP143's role in this process is not well understood. Here, we tagged both CTCF and ZFP143 with dual-purpose degron/imaging tags to combinatorially assess their looping function and effect on each other. We find that ZFP143 possesses no general looping function, and that it largely functions independently of CTCF. Instead, ZFP143 is an essential transcription factor possessing an extremely stable chromatin residence time regulating an important subset of housekeeping genes.