Paraspeckles are membraneless organelles formed through liquid-liquid phase separation and consist of multiple proteins and RNAs, including NONO, SFPQ, and NEAT1. The role of paraspeckles and the component NONO in hematopoiesis remains unknown. In this study, we show histone modifier ASXL1 is involved in paraspeckle formation. ASXL1 forms phase-separated droplets, upregulates NEAT1 expression, and increases NONO-NEAT1 interactions through the C-terminal intrinsically disordered region (IDR). In contrast, a pathogenic ASXL mutant (ASXL1-MT) lacking IDR does not support the interaction of paraspeckle components. Furthermore, paraspeckles are disrupted and Nono localization is abnormal in the cytoplasm of hematopoietic stem and progenitor cells (HSPCs) derived from ASXL1-MT knockin mice. Nono depletion and the forced expression of cytoplasmic NONO impair the repopulating potential of HSPCs, as does ASXL1-MT. Our study indicates a link between ASXL1 and paraspeckle components in the maintenance of normal hematopoiesis.
Publication: Cell Reports
Title: A histone modifier ASXL1 interacts with NONO and is involved in paraspeckle formation in hematopoietic cells
Authors: Keita Yamamoto, Susumu Goyama, Shuhei Asada, Takeshi Fujino, Taishi Yonezawa, Naru Sato, Reina Takeda, Akiho Tsuchiya, Tomofusa Fukuyama, Yosuke Tanaka, Akihiko Yokoyama, Hikaru Toya, Ayana Kon, Yasuhito Nannya, Rena Onoguchi-Mizutani, Shinichi Nakagawa, Tetsuro Hirose, Seishi Ogawa, Nobuyoshi Akimitsu, and Toshio Kitamura*