JCB logo
PeproTech: Cell Culture Supplements
  Home | Help | Feedback | Subscriptions | Archive | Search | Table of Contents
This Article
Right arrow Full Text
Right arrow Full Text (PDF, 953K)
Right arrow PPT slides of all figures
Right arrow Alert me when this article is cited
Right arrow Citation Map
Services
Right arrow Email this article
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new content in the JCB
Right arrow Download to citation manager
Citing Articles
Right arrow Citing Articles via CrossRef
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Verheggen, C.
Right arrow Articles by Hernandez-Verdun, D.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Verheggen, C.
Right arrow Articles by Hernandez-Verdun, D.
Social Bookmarking
Add to CiteULike   Add to Complore   Add to Connotea   Add to Del.icio.us   Add to Digg   Add to Facebook   Add to Reddit   Add to Technorati   Add to Twitter  
What's this?

© The Rockefeller University Press, 0021-9525/2000//293 $5.00
The Journal of Cell Biology, Volume 149, Number 2, , 2000 293-306

Original Article

The Ribosomal RNA Processing Machinery Is Recruited to the Nucleolar Domain before RNA Polymerase I during Xenopus laevis Development



Céline Verheggena,b, Geneviève Almouznib, and Danièle Hernandez-Verduna

a Institut Jacques Monod, UMR 7592, 75251 Paris, France
b Institut Curie, Section de Recherche, UMR 144, 75248 Paris, France
Institut Jacques Monod, 2 place Jussieu, 75251 Paris Cedex 05, France.331 44 27 59 94331 44 27 40 38

dhernand{at}ccr.jussieu.fr

Transcription and splicing of messenger RNAs are temporally and spatially coordinated through the recruitment by RNA polymerase II of processing factors. We questioned whether RNA polymerase I plays a role in the recruitment of the ribosomal RNA (rRNA) processing machinery. During Xenopus laevis embryogenesis, recruitment of the rRNA processing machinery to the nucleolar domain occurs in two steps: two types of precursor structures called prenucleolar bodies (PNBs) form independently throughout the nucleoplasm; and components of PNBs I (fibrillarin, nucleolin, and the U3 and U8 small nucleolar RNAs) fuse to the nucleolar domain before components of PNBs II (B23/NO38). This fusion process is independent of RNA polymerase I activity, as shown by actinomycin D treatment of embryos and by the lack of detectable RNA polymerase I at ribosomal gene loci during fusion. Instead, this process is concomitant with the targeting of maternally derived pre-rRNAs to the nucleolar domain. Absence of fusion was correlated with absence of these pre-rRNAs in nuclei where RNA polymerase II and III are inhibited. Therefore, during X. laevis embryogenesis, the recruitment of the rRNA processing machinery to the nucleolar domain could be dependent on the presence of pre-rRNAs, but is independent of either zygotic RNA polymerase I transcription or the presence of RNA polymerase I itself.

Key Words: prenucleolar body • nucleologenesis • pre-rRNA • RNA polymerase I transcription • Xenopus laevis development

© 2000 The Rockefeller University Press

Abbreviations used in this paper: Br-UTP, 5-bromouridine-5'-triphosphate; DAPI, 4'-6-diamidino-2-phenylindole dihydrochloride; ETS, external transcribed spacers; FISH, fluorescent in situ hybridization; ITS, internal transcribed spacers; MBT, midblastula transition; mRNA, messenger RNA; PNB, prenucleolar bodies; rDNA, ribosomal gene; rRNA, ribosomal RNA; RNA pol I, RNA polymerase I; snoRNA, small nucleolar RNA.


Add to CiteULike CiteULike   Add to Complore Complore   Add to Connotea Connotea   Add to Del.icio.us Del.icio.us   Add to Digg Digg   Add to Facebook Facebook   Add to Reddit Reddit   Add to Technorati Technorati   Add to Twitter Twitter    What's this?




  Home | Help | Feedback | Subscriptions | Archive | Search | Table of Contents