Nuclear Retention of Unspliced mRNAs in Yeast Is Mediated by Perinuclear Mlp1

• Published in: Cell Vol. 116; no. 1; pp. 63 - 73
• Main Authors: Galy, Vincent, Gadal, Olivier, Fromont-Racine, Micheline, Romano, Alper, Jacquier, Alain, Nehrbass, Ulf
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 09.01.2004; Elsevier
• Subjects: Active Transport, Cell Nucleus; Active Transport, Cell Nucleus - genetics; Cell Nucleus; Cell Nucleus - genetics; Cell Nucleus - metabolism; Cellular Biology; Exoribonucleases; Exoribonucleases - deficiency; Exoribonucleases - genetics; Exosome Multienzyme Ribonuclease Complex; Introns; Introns - genetics; Life Sciences; Mlp1 protein; Mutation; Mutation - genetics; Nuclear Envelope; Nuclear Envelope - genetics; Nuclear Envelope - metabolism; Nuclear Pore Complex Proteins; Nuclear Pore Complex Proteins - genetics; Nuclear Pore Complex Proteins - metabolism; Nuclear Proteins; Nuclear Proteins - deficiency; Nuclear Proteins - genetics; Nuclear Proteins - metabolism; Protein Transport; Protein Transport - genetics; Ribonucleoprotein, U5 Small Nuclear; RNA Splice Sites; RNA Splice Sites - genetics; RNA Splicing; RNA Splicing - genetics; RNA, Messenger; RNA, Messenger - genetics; RNA, Messenger - metabolism; RNA-Binding Proteins; RRP6 gene; Saccharomyces cerevisiae; Saccharomyces cerevisiae Proteins; Saccharomyces cerevisiae Proteins - genetics; Saccharomyces cerevisiae Proteins - metabolism; Subcellular Processes; Yeasts; Yeasts - genetics; Yeasts - metabolism
• ISSN: 0092-8674; 1097-4172
• DOI: 10.1016/S0092-8674(03)01026-2

The molecular mechanism underlying the retention of intron-containing mRNAs in the nucleus is not understood. Here, we show that retention of intron-containing mRNAs in yeast is mediated by perinuclearly located Mlp1. Deletion of MLP1 impairs retention while having no effect on mRNA splicing. The Mlp1-dependent leakage of intron-containing RNAs is increased in presence of ts-prp18Δ, a splicing mutant. When overall pre-mRNA levels are increased by deletion of RRP6, a nuclear exosome component, MLP1 deletion augments leakage of only the intron-containing portion of mRNAs. Our data suggest, moreover, that Mlp1-dependent retention is mediated via the 5′ splice site. Intriguingly, we found Mlp-proteins to be present only on sections of the NE adjacent to chromatin. We propose that at this confined site the perinuclear Mlp1 implements a quality control step prior to export, physically retaining faulty pre-mRNAs.