A novel role for Sem1 and TREX-2 in transcription involves their impact on recruitment and H2B deubiquitylation activity of SAGA

Abstract

Transcription and mRNA export are linked processes. However, the molecular mechanisms of this coordination are not clear. Sus1 (hENY2) participates in this coordination as part of two protein complexes: SAGA, a transcriptional co-activator; TREX-2, which functions in mRNA biogenesis and export. Here, we investigate the coordinated action of SAGA and TREX-2 required for gene expression. We demonstrate that TREX-2 subunit Sem1 also participates in transcription activation. Like Sus1, Sem1 is required for the induction of ARG1 and GAL1, these being SAGA-regulated genes. Chromatin immunoprecipitations show that proper recruitment of certain SAGA subunits to the GAL1 promoter depends on Sem1. Notably, both in vivo and in vitro analyses reveal that Sem1 influences SAGA-dependent histone H2B deubiquitylation. Most of these phenotypes are also found to depend on another TREX-2 subunit, Thp1. These results unveil a new role for Sem1 in the activation of the SAGA-dependent gene GAL1 and influencing H2B deubiquitylation. Our work provides insights into a novel functional relationship between Sem1 and the SAGA complex.

A multi-omics dataset of heat-shock response in the yeast RNA binding protein Mip6

“…Yeast is an ideal research model for transcriptome research because they exhibit most of the cellular complexity present in eukaryotes and have relatively compact, accessible genomes. However, while the interconnected transcriptional circuit has been studied and accepted by many yeast labs 2,[10][11][12][13][14][15] , these studies usually target aspects of the transcriptional regulation and produce separate results that contribute to the overall transcriptional model. Moreover, different strains, experimental conditions and batches are used by different labs and there are few examples of experimental datasets where all these layers have been measured on exactly the same samples.…”

A role for Mog1 in H2Bub1 and H3K4me3 regulation affecting RNAPII transcription and mRNA export

“…Chromatin immunoprecipitation was performed as previously described [,] using 50 ml of yeast cultures grown to an OD 600 of 0.5 in YP + Glucose. Cultures were cross‐linked for 20 min at room temperature with formaldehyde (1% final concentration; Sigma) and were later quenched with 125 mM glycine.…”

“…Chromatin immunoprecipitation was performed as previously described [37,73] Samples were eluted by adding 50 ll of elution buffer (50 mM Tris-HCl, pH 8, 10 mM EDTA, 1% SDS) to the beads and incubating for 10 min at 65°C. This step was repeated twice.…”

“…For instance, Sus1, a component of both SAGA DUBm and TREX-2 complexes, plays a key role in coupling transcription activation, H2Bub1 deubiquitination, and mRNA export [34]. It has also been shown that deletion of either DUBm subunits Sgf11 or Sgf73 exacerbates mRNA export defects [35,36], while the TREX-2 subunit Sem1 is required for SAGA-dependent deubiquitinating activity [37]. These data highlight the bidirectional functional connection between the two complexes.…”

Study of the SAGA deubiquitination module: identification of new modulators and its implication on Spinocerebellar Ataxia Type 7

“…With this work, we demonstrated that Sem1 component from TREX-2 complex also facilitates the linkage between SAGA and TREX-2 since Sem1 is required for the induction of SAGA regulated genes GAL1 and ARG1 and it also takes part in SAGA-dependent deubiquitination activity (García-Oliver et al, 2013).…”