The nuclear DEAD box RNA helicase p68 interacts with the nucleolar proteinfibrillarin and colocalizes specifically in nascent nucleoli during telophase

Citation
Sm. Nicol et al., The nuclear DEAD box RNA helicase p68 interacts with the nucleolar proteinfibrillarin and colocalizes specifically in nascent nucleoli during telophase, EXP CELL RE, 257(2), 2000, pp. 272-280
Citations number
27
Categorie Soggetti
Cell & Developmental Biology
Journal title
EXPERIMENTAL CELL RESEARCH
ISSN journal
00144827 → ACNP
Volume
257
Issue
2
Year of publication
2000
Pages
272 - 280
Database
ISI
SICI code
0014-4827(20000615)257:2<272:TNDBRH>2.0.ZU;2-C
Abstract
The DEAD box protein, p68, is an established RNA-dependent ATPase and RNA h elicase in vitro, but neither the physiological function of this protein no r the macromolecules with which it interacts are known. Using a yeast two-h ybrid screen, we identified the nucleolar protein, fibrillarin, as a protei n that interacts with p68. Coimmunoprecipitation experiments confirmed that p68 and fibrillarin can form complexes in cellular extracts, and deletion analysis identified regions in each protein responsible for mediating the i nteraction. Immunofluorescence studies using confocal microscopy revealed t hat, in interphase cells, while fibrillarin is predominantly nucleolar, p68 shows a diffuse granular nuclear staining but is largely excluded from the nucleoli. Strikingly, both proteins colocalize in nascent nucleoli during late telophase. These data are consistent with a role for p68 either in pos tmitotic nucleolar reassembly or in the activation of ribosomal DNA transcr iption/preribosomal RNA processing during telophase and suggest that differ ential subnuclear compartmentalization mag be a mechanism by which interact ion of p68 with fibrillarin is regulated in the cell. (C) 2000 Academic Pre ss.