Title: Db The transcription elongation factor Rtf1 regulates distribution of the nucleosome remodeler Chd1 on active genes
Abstract:
Nucleosomes impede DNA-templated processes and enforce transcriptional fidelity by preventing transcription from aberrant start sites. The nucleosome remodeler Chd1 dynamically controls nucleosome positioning genome-wide, but it is unclear how Chd1 function is regulated and whether Chd1 recruitment to chromatin is related to the transcription cycle. Our lab previously found that the transcription elongation factor Rtf1, a member of the Paf1 Complex (Paf1C), interacts with Chd1 and is partly responsible for Chd1 occupancy on chromatin in yeast. Through site-directed mutagenesis and yeast two-hybrid experiments, we have localized the interacting regions of Rtf1 and Chd1 and designed mutations in both proteins that disrupt the interaction. Further, we have shown that Rtf1 and Chd1 have a direct physical interaction. Through ChIP-seq and MNase-seq experiments, we found that a few conserved amino acids in the N-terminal region of Rtf1 and a relatively uncharacterized C-terminal region of Chd1 are required for proper distribution of Chd1 along gene bodies and normal nucleosome positioning at Chd1-occupied genes. Resident histone modifications are likewise shifted when the Rtf1-Chd1 interaction is lost. Mutations in RTF1 or CHD1 lead to cryptic intragenic transcription, demonstrating the importance of the Rtf1-Chd1 interaction for proper transcriptional control and chromatin function. Using a yeast two-hybrid approach, we demonstrate that mouse RTF1 similarly interacts with both mouse CHD1 and CHD2, consistent with the high conservation of these interacting protein domains in mammals. We have generated cell lines to test this interaction in mouse embryonic stem cells and we are currently exploring how RTF1, CHD1, and CHD2 chromatin occupancy and chromatin accessibility is altered. Together, these data indicate that Rtf1 and Chd1 function together during transcription to facilitate nucleosome remodelling in yeast and suggest a conserved interaction between mouse RTF1 with CHD1 and CHD2.
Arndt/Hainer Lab
Friday, April 26th, 2024
12:00PM
Langley A219B