Present address: Institut de Génétique Moléculaire de Montpellier, CNRS-UMR 5535, 1919 Route de Mende, 34293 Montpellier-Cedex 5, France.
AtNUFIP, an essential protein for plant development, reveals the impact of snoRNA gene organisation on the assembly of snoRNPs and rRNA methylation in Arabidopsis thaliana
Article first published online: 24 JAN 2011
© 2011 The Authors. The Plant Journal © 2011 Blackwell Publishing Ltd
The Plant Journal
Volume 65, Issue 5, pages 807–819, March 2011
How to Cite
Rodor, J., Jobet, E., Bizarro, J., Vignols, F., Carles, C., Suzuki, T., Nakamura, K. and Echeverría, M. (2011), AtNUFIP, an essential protein for plant development, reveals the impact of snoRNA gene organisation on the assembly of snoRNPs and rRNA methylation in Arabidopsis thaliana. The Plant Journal, 65: 807–819. doi: 10.1111/j.1365-313X.2010.04468.x
- Issue published online: 24 FEB 2011
- Article first published online: 24 JAN 2011
- Accepted manuscript online: 24 DEC 2010 10:09AM EST
- Received 3 September 2010; revised 6 December 2010; accepted 18 December 2010; published online 24 January 2011.
- snoRNP assembly;
- atnuf mutants;
- rRNA methylation
In all eukaryotes, C/D small nucleolar ribonucleoproteins (C/D snoRNPs) are essential for methylation and processing of ribosomal RNAs. They consist of a box C/D small nucleolar RNA (C/D snoRNA) associated with four highly conserved nucleolar proteins. Recent data in HeLa cells and yeast have revealed that assembly of these snoRNPs is directed by NUFIP protein and other auxiliary factors. Nevertheless, the precise function and biological importance of NUFIP and the other assembly factors remains unknown. In plants, few studies have focused on RNA methylation and snoRNP biogenesis. Here, we identify and characterise the AtNUFIP gene that directs assembly of C/D snoRNP. To elucidate the function of AtNUFIP in planta, we characterized atnufip mutants. These mutants are viable but have severe developmental phenotypes. Northern blot analysis of snoRNA accumulation in atnufip mutants revealed a specific degradation of C/D snoRNAs and this situation is correlated with a reduction in rRNA methylation. Remarkably, the impact of AtNUFIP depends on the structure of snoRNA genes: it is essential for the accumulation of those C/D snoRNAs encoded by polycistronic genes, but not by monocistronic or tsnoRNA genes. We propose that AtNUFIP controls the kinetics of C/D snoRNP assembly on nascent precursors to overcome snoRNA degradation of aberrant RNPs. Finally, we show that AtNUFIP has broader RNP targets, controlling the accumulation of scaRNAs that direct methylation of spliceosomal snRNA in Cajal bodies.