GSE1 is a prominent interactor of HDAC1

We analysed the composition of histone acetylase 1 (HDAC1)-associated proteins in different cellular backgrounds using quantitative mass spectrometry (MS). First, we affinity purified (AP) C-terminally FLAG-tagged HDAC1 from the nearly haploid human cell line HAP1 (Andersson et al, 1987). To examine cross-species conservation in the composition of HDAC1 complexes we additionally analysed HDAC1-FLAG purifications from mouse embryonic fibroblasts (MEFs). Genetic suppressor element 1 (GSE1) was identified as a prominent interaction partner of HDAC1. Hence, we purified V5-tagged GSE1 from HAP1 cells and analysed co-precipitated proteins.