Changes of the Nucleolus Architecture in Absence of the Nuclear Factor CTCF

Abstract

CTCF is a multifunctional nuclear factor involved in many cellular processes like gene regulation, chromatin insulation and genomic organization. Recently, CTCF has been shown to be involved in the transcriptional regulation of ribosomal genes and nucleolar organization in Drosophila cells and different murine cell types, including embryonic stem cells. Moreover, it has been suggested that CTCF could be associated to the nucleolus of human erythroleukemic K562 cells. In the present work, we took advantage of efficient small hairpin RNA interference against human CTCF to analyze nucleolar organization in HeLa cells. We have found that key components of the nucleolar architecture are altered. As a consequence of such alterations, an upregulation of ribosomal gene transcription was observed. We propose that CTCF contributes to the structural organization of the nucleolus and, through epigenetic mechanisms, to the regulation of the ribosomal gene expression.

Improved transcription and translation with L-leucine stimulation of mTORC1 in Roberts syndrome

“…However, we have previously provided evidence that acetylated cohesin promotes expression of the ribosomal DNA repeats and the formation of nucleoli. CTCF is also important for the formation of nucleoli [ 64 ]. Nucleoli likely provide a keystone for genome architecture [ 64 – 67 ], suggesting that disruption in the organization of rDNA could have extensive effects on the organization and expression of most chromosomes such as that observed at NADs.…”

“…CTCF is also important for the formation of nucleoli [ 64 ]. Nucleoli likely provide a keystone for genome architecture [ 64 – 67 ], suggesting that disruption in the organization of rDNA could have extensive effects on the organization and expression of most chromosomes such as that observed at NADs. In the future it will be interesting to analyze chromosome organization in the absence of ESCO2 function and how this impacts gene expression.…”

A Cell Cycle Role for the Epigenetic Factor CTCF-L/BORIS

“…Furthermore, exogenous GFP-BORIS accumulated in the nucleolus of human epithelial cells. While this work was being revised, [57] reported nucleolar localisation of BORIS in cultured cell lines and [63], reported changes in the architecture of the nucleolus in the absence of CTCF. BORIS and CTCF exhibit high homology in the central 11 Zinc-Finger domain.…”

Loss of Nucleolar Histone Chaperone NPM1 Triggers Rearrangement of Heterochromatin and Synergizes with a Deficiency in DNA Methyltransferase DNMT3A to Drive Ribosomal DNA Transcription

“…One interaction partner of NPM1 is CTCF, a sequence-specific DNA-binding protein that delimits the juxtaposed domains of active and inactive chromatin (65,66). CTCF loss resulted in nucleolar fragmentation and reduced rDNA silencing in HeLa cells (67) as well as in Drosophila (68). Importantly, CTCF associates with NPM1, and both proteins are present at insulator sites in HeLa cells (65).…”