Duncalf Louise, Wang Xinru, Aljabri Abdulrahman A, Campbell Amy E, Alharbi Rawan Q, Donaldson Ian, Hayes Andrew, Peti Wolfgang, Page Rebecca, Bennett Daimark
Faculty of Health and Life Sciences, University of Liverpool, Biosciences Building, Crown Street, L69 7ZB Liverpool, UK.
Department of Molecular Biology, Cell Biology and Biochemistry, Brown University, Providence, RI, USA.
Cell Rep. 2025 May 27;44(5):115693. doi: 10.1016/j.celrep.2025.115693. Epub 2025 May 9.
Ser/Thr protein phosphatase 1 (PP1) forms a large nuclear holoenzyme (with PNUTS, WDR82, and Tox4) whose emerging role is to regulate transcription. However, the role of Tox4, and its interplay with the other phosphatase subunits in this complex, is poorly understood. Here, we combine biochemical, structural, cellular, and in vivo experiments to show that, while tox4 is dispensable for viability, it is essential for fertility, having both PNUTS-dependent and -independent roles in Drosophila germline development. We also show that Tox4 requires zinc for PNUTS TFIIS N-terminal domain (TND) binding, and that it binds the TND on a surface distinct from that used by established TND-interacting transcriptional regulators. We also show that selective disruption of the PNUTS-Tox4 and the PNUTS-PP1 interaction is critical for normal gene expression and chromosomal dispersal during oogenesis. Together, these data demonstrate how interactions within the PNUTS-Tox4-PP1 phosphatase combine to tune transcriptional outputs driving developmental transitions.
丝氨酸/苏氨酸蛋白磷酸酶1（PP1）形成一种大型核全酶（与PNUTS、WDR82和Tox4一起），其新出现的作用是调节转录。然而，Tox4的作用及其与该复合物中其他磷酸酶亚基的相互作用尚不清楚。在这里，我们结合生化、结构、细胞和体内实验表明，虽然tox4对生存能力并非必需，但对生育能力至关重要，在果蝇生殖系发育中具有依赖PNUTS和不依赖PNUTS的作用。我们还表明，Tox4需要锌来结合PNUTS TFIIs N端结构域（TND），并且它在与已确定的TND相互作用转录调节因子不同的表面结合TND。我们还表明，选择性破坏PNUTS-Tox4和PNUTS-PP1相互作用对于卵子发生过程中的正常基因表达和染色体分散至关重要。总之，这些数据证明了PNUTS-Tox4-PP1磷酸酶内的相互作用如何结合起来调节驱动发育转变的转录输出。
