Figure - PMC

Skip to main content

An official website of the United States government

Here's how you know

Here's how you know

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure .gov websites use HTTPS
A lock ( ) or https:// means you've safely connected to the .gov website. Share sensitive information only on official, secure websites.

View full-text article in PMC

. 1998 Sep 7;142(5):1167–1180. doi: 10.1083/jcb.142.5.1167

Search in PMC
Search in PubMed
View in NLM Catalog
Add to search

This article is distributed under the terms of an Attribution–Noncommercial–Share Alike–No Mirror Sites license for the first six months after the publication date (see http://www.rupress.org/terms). After six months it is available under a Creative Commons License (Attribution–Noncommercial–Share Alike 4.0 Unported license, as described at http://creativecommons.org/licenses/by-nc-sa/4.0/).

PMC Copyright notice

Nuclear events described in this work. Percentage of embryonic nuclei are expressed as a function of time after fertilization. Schematic representations of the embryos at the different times are presented below the graph. The first event described was UBF association with rDNAs in nearly all embryonic nuclei at every time after fertilization ( ). Regroupment of fibrillarin and nucleolin to the nucleolar domain ( ) as well as maternal pre-rRNAs ( ) were observed in a growing fraction of embryonic nuclei between 7 and 13 h after fertilization. The curve corresponding to RNA pol II or pol III activities detected by run-on assays in nuclei ( ) was identical to the two latter curves since transcription activities were detected in nuclei in that nucleolar proteins and maternal pre-rRNAs were regrouped. However, onset of RNA pol I activity was not concomitant with this regroupment. The curve expressing the percentage of nuclei with RNA pol I activity ( ) shows a delay of ∼2.5 h. For simplification, the period that comprises the recruitment of nuclei competent for RNA pol II transcription will be referred to as MBT and the periods before or after as pre-MBT or post-MBT, respectively.

Inline graphic — Nuclear events described in this work. Percentage of embryonic nuclei are expressed as a function of time after fertilization. Schematic representations of the embryos at the different times are presented below the graph. The first event described was UBF association with rDNAs in nearly all embryonic nuclei at every time after fertilization ( ). Regroupment of fibrillarin and nucleolin to the nucleolar domain ( ) as well as maternal pre-rRNAs ( ) were observed in a growing fraction of embryonic nuclei between 7 and 13 h after fertilization. The curve corresponding to RNA pol II or pol III activities detected by run-on assays in nuclei ( ) was identical to the two latter curves since transcription activities were detected in nuclei in that nucleolar proteins and maternal pre-rRNAs were regrouped. However, onset of RNA pol I activity was not concomitant with this regroupment. The curve expressing the percentage of nuclei with RNA pol I activity ( ) shows a delay of ∼2.5 h. For simplification, the period that comprises the recruitment of nuclei competent for RNA pol II transcription will be referred to as MBT and the periods before or after as pre-MBT or post-MBT, respectively.