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Updated: Aug 4, 2026

Engineering Artificial Factors to Specifically Manipulate Alternative Splicing in Human Cells
Published on: April 26, 2017
Nuclear PtdIns(4,5)P2 assembles in a mitotically regulated particle involved in pre-mRNA splicing
S L Osborne1, C L Thomas, S Gschmeissner
1Molecular Neuropathobiology Laboratory, Imperial Cancer Research Fund, 44 Lincoln's Inn Fields, London, WC2A 3PX, UK.
Abstract:
Phosphoinositide turnover regulates multiple cellular processes. Compared with their well-known cytosolic roles, limited information is available on the functions of nuclear phosphoinositides. Here, we show that phosphatidylinositol(4,5)-bisphosphate (PtdIns(4,5)P2) stably associates with electron-dense particles within the nucleus that resemble interchromatin granule clusters. These PtdIns(4,5)P2-containing structures have a distribution which is cell-cycle dependent and contain components of both the transcriptional and pre-mRNA processing machinery, including RNA polymerase II and the splicing factor SC-35. Immunodepletion and add-back experiments demonstrate that PtdIns(4,5)P2 and associated factors are necessary but not sufficient for pre-mRNA splicing in vitro, indicating a crucial role for PtdIns(4,5)P2-containing complexes in nuclear pre-mRNA processing.
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