EWSR1 maintains centromere identity

The centromere is essential for ensuring high-fidelity transmission of chromosomes. CENP-A, the centromeric histone H3 variant, is thought to be the epigenetic mark of centromere identity. CENP-A deposition at the centromere is crucial for proper centromere function and inheritance. Despite its importance, the precise mechanism responsible for maintenance of centromere position remains obscure. Here, we report a mechanism to maintain centromere identity. We demonstrate that CENP-A interacts with EWSR1 (Ewing sarcoma breakpoint region 1) and EWSR1-FLI1 (the oncogenic fusion protein in Ewing sarcoma). EWSR1 is required for maintaining CENP-A at the centromere in interphase cells. EWSR1 and EWSR1-FLI1 bind CENP-A through the SYGQ2 region within the prion-like domain, important for phase separation. EWSR1 binds to R-loops through its RNA-recognition motif in vitro. Both the domain and motif are required for maintaining CENP-A at the centromere. Therefore, we conclude that EWSR1 guards CENP-A in centromeric chromatins by binding to centromeric RNA. [Display omitted] •EWSR1 is required to maintain CENP-A at the centromere in interphase cells•EWSR1 binds to CENP-A through the SYGQ2 region, important for phase separation•EWSR1 binds to R loops in vitro through its RNA-recognition motif (RRM)•EWSR1 protects CENP-A in the centromeric chromatin by binding to centromeric RNAs Kitagawa et al. report a novel mechanism for maintaining the position of the centromere on the chromosome, i.e., centromere identity. EWSR1 (Ewing sarcoma breakpoint region 1) is required for CENP-A deposition at centromeres by binding to centromeric RNA. EWSR1 guards CENP-A in centromeric chromatin by binding to centromeric RNA.