Mediator is a coregulatory complex involved in regulating the transcription of Pol II-dependent genes. Metazoan Mediator subunit MED26 functions as a docking site for the ELL/EAF-containing Super Elongation Complex (SEC) and L ittle Elongation Complex (LEC), which regulate the expression of distinct genes. MED26 helps to recruit SEC to protein-coding genes including c-Myc and LEC to small nuclear RNA (snRNA) genes. However, why MED26 takes advantage of SEC or LEC to regulate different claases of genes is unclear. Here, we present evidence that MED26 recruits LEC to support optimal transcription termination at non-polyadenylated genes including snRNA and replication-dependent histone (RDH) genes. Our findings indicate that LEC recruited by MED26 promotes efficient transcription termination by Pol II through interaction with CBC-ARS2 and NELF/DSIF, and then LEC promotes 3-end processing through the recruitment of Integrator or Heat labile factor to snRNA or RDH genes, respectively. SOURCE: Shiyuan,(Cynthia),Chen (shc@stowers.org) -  Showers Institute for Medical Research

Pluto Bioinformatics

GSE121024: The role of Mediator and Little Elongation Complex in transcription termination