variant Polycomb Repressive complexes 1 (vPRC1s) in synovial sarcoma

Several variant Polycomb Repressive complexes 1 (vPRC1s) co-exist to robustly deposit mono ubiquitination on histone H2A (H2AK119ub1). Their interconnected roles and specific tasks across normal and disease cellular states remain unclear. In synovial sarcoma (SS), a soft tissue tumor driven by the oncogenic fusion protein, SS18::SSX, the SSX tail exhibits a high affinity to H2AK119ub1 marked genomic regions. This mechanism is crucial to sequester the mSWI/SNF complex to PRC1 targets and results in their aberrant expression. We previously showed that PRC1.1 is responsible for H2AK119ub1 deposition in SS and is therefore required for SS18::SSX occupancy. Here, we investigated the role of PRC1 variants in synovial sarcoma. Total RNA from two independent experiments was extracted using a RNeasy mini kit (Qiagen). RNA-Seq library preparation and sequencing were performed at the High Throughput Sequencing Unit of the Genomics & Proteomics core facility of DKFZ using TruSeq Stranded Total RNA Library Prep kit (Illumina) and HiSeq 2000 v4 single-read 50bp sequencing system.