Involvement of PIP2 in RNA Polymerase I transcription

• DOI: 10.1242/jcs.123661
• Publication Date: 2013-04-17T04:48:47Z
• Authors: Sukriye Yildirim; Enrique Castano; Margarita Sobol; Vlada V. Philimon...; Rastislav Dzijak; Tomáš Venit; Pavel Hozák
• Keywords: Phosphatidylinositol 4,5-Diphosphate; 0303 health sciences; Transcription, Genetic; Chromosomal Proteins, Non-Histone; fibrillarin; DNA-Binding Proteins; 03 medical and health sciences; PIP2; UBF; RNA Polymerase I; Cell Line, Tumor; RNA Precursors; Humans; nucleolus; transcription; Promoter Regions, Genetic; Pol1 Transcription Initiation Complex Proteins; Cell Nucleolus; HeLa Cells

RNA polymerase I (Pol I) transcription is essential for the cell cycle, growth, and overall protein synthesis in eukaryotes. We found that phosphatidylinositol 4,5-bisphosphate (PIP2) is a part of the protein complex on the active ribosomal promoter during the transcription. PIP2 makes a complex with Pol I and Pol I transcription factor UBF in the nucleolus. PIP2 depletion reduces Pol I transcription which can be rescued by the addition of exogenous PIP2. In addition, PIP2 also binds directly to the pre-rRNA processing factor, fibrillarin (Fib), and co-localizes with nascent transcripts in the nucleolus. PIP2 binding to UBF and Fib modulates their binding to DNA and RNA, respectively. In conclusion, PIP2 interacts with a subset of Pol I transcription machinery, and promotes Pol I transcription.