MCDB seminar will be from Tasniem Fetian from the Arndt lab will be presenting their research titled:
Title: Investigating the functions and interplay of co-transcriptional nucleosome modifications
Friday, February 7, 2025
A219B Langley Hall
12:00 PM
The wrapping of eukaryotic DNA around histones to form nucleosomes allows efficient DNA packaging but is an obstacle for DNA-templated transactions. Multiple regulatory mechanisms have therefore emerged to modulate nucleosomal properties and DNA accessibility. Monoubiquitylation of H2B (H2Bub) on K123 in budding yeast (K120 in humans) is a dynamic co-transcriptional histone modification that modulates chromatin on structural and functional levels. In yeast and higher eukaryotes, the Paf1C transcription elongation factor is required for H2Bub and facilitates its coupling to transcription. A small domain within the Rtf1 subunit of Paf1C, named the Histone Modification Domain (HMD), directly interacts with the ubiquitin conjugase Rad6 leading to H2Bub stimulation. While the molecular events that couple H2Bub to transcription are coming more into focus, the direct contributions of this conserved modification to transcription and its coordination with other epigenetic modifications remain to be fully elucidated. Genetic studies revealed a synthetic lethal relationship between H2Bub and H2A.Z, the H2A histone variant that is enriched at the +1 nucleosome of genes. Such interaction suggests that H2A.Z and H2Bub have overlapping functions that would normally compensate for each other. Although H2Bub and H2A.Z are associated with the transcription of almost all genes, their interplay and direct contributions to global transcription mechanisms are poorly understood. My ongoing genetic and genomic experiments are directed towards investigating the impact on the transcriptome upon the concurrent loss of H2A.Z and H2Bub and pinpointing mechanisms that are responsible for the synthetic lethality.