Du, X. and Rao, M.R.K.S. and Chen, X.Q. and Wu, W. and Mahalingam, S. and Balasundaram, D. (2006) The Homologous Putative GTPases Grn1p from Fission Yeast and the Human GNL3L Are Required for Growth and Play a Role in Processing of Nucleolar Pre-rRNA. Molecular Biology of the Cell, 17 (1). pp. 460-474. ISSN 1059-1524

Preview

Text Mol Biol Cell 17 p460.pdf Download (726Kb) | Preview

Abstract

Grn1p from fission yeast and GNL3L from human cells, two putative GTPases from the novel HSR1_MMR1 GTP-binding protein subfamily with circularly permuted G-motifs play a critical role in maintaining normal cell growth. Deletion of Grn1 resulted in a severe growth defect, a marked reduction in mature rRNA species with a concomitant accumulation of the 35S pre-rRNA transcript, and failure to export the ribosomal protein Rpl25a from the nucleolus. Deleting any of the Grn1p G-domain motifs resulted in a null phenotype and nuclear/nucleolar localization consistent with the lack of nucleolar export of preribosomes accompanied by a distortion of nucleolar structure. Heterologous expression of GNL3L in a Deltagrn1 mutant restored processing of 35S pre-rRNA, nuclear export of Rpl25a and cell growth to wild-type levels. Genetic complementation in yeast and siRNA knockdown in HeLa cells confirmed the homologous proteins Grn1p and GNL3L are required for growth. Failure of two similar HSR1_MMR1 putative nucleolar GTPases, Nucleostemin (NS), or the dose-dependent response of breast tumor autoantigen NGP-1, to rescue deltagrn1 implied the highly specific roles of Grn1p or GNL3L in nucleolar events. Our analysis uncovers an important role for Grn1p/GNL3L within this unique group of nucleolar GTPases.

Item Type:	Article
Depositing User:	Users 2 not found.
Date Deposited:	29 Jul 2015 11:35
Last Modified:	29 Nov 2015 17:37
URI:	http://cdfd.sciencecentral.in/id/eprint/310

Actions (login required)

View Item