scholarly journals MicroRNA-directed transcriptional gene silencing in mammalian cells

2008 ◽  
Vol 105 (42) ◽  
pp. 16230-16235 ◽  
Author(s):  
D. H. Kim ◽  
P. Saetrom ◽  
O. Snove ◽  
J. J. Rossi
Keyword(s):  
Gene Silencing ◽  
Mammalian Cells ◽  
Transcriptional Gene Silencing

scholarly journals siRNA Induced Transcriptional Gene Silencing in Mammalian Cells

Cell Cycle ◽  
2005 ◽  
Vol 4 (3) ◽  
pp. 442-448 ◽  
Author(s):  
Hiroaki Kawasaki ◽  
Kazumari Taira ◽  
Kevin V. Morris
Keyword(s):  
Gene Silencing ◽  
Mammalian Cells ◽  
Transcriptional Gene Silencing

scholarly journals A Truncated Form of the Human CAF-1 p150 Subunit Impairs the Maintenance of Transcriptional Gene Silencing in Mammalian Cells

2001 ◽  
Vol 21 (6) ◽  
pp. 1953-1961 ◽  
Author(s):  
Thierry Tchénio ◽  
Jean-François Casella ◽  
Thierry Heidmann
Keyword(s):  
Gene Silencing ◽  
Reporter Gene ◽  
Mammalian Cells ◽  
Cell Model ◽  
Methylation Status ◽  
Dominant Negative ◽  
Transcriptional Gene Silencing ◽  
Dominant Negative Mutant ◽  
Control Of Gene Expression ◽  
Gene Copies

ABSTRACT Chromatin assembly factor 1 (CAF-1) is a protein complex formed of three subunits, p150, p60, and p48, conserved from the yeast Saccharomyces cerevisiae to humans, which can promote nucleosome assembly onto newly replicated DNA. In S. cerevisiae, deletion of the genes encoding any of the three CAF-1 subunits (cacΔ mutants), although nonlethal, results in a silencing defect of genes packaged into heterochromatin. Here we report on a mammalian cell model that we devised to monitor gene silencing and its reversal in a quantitative manner. This model relies on the use of a cell line stably transfected with a reporter gene in a silenced state. Reversal of reporter gene silencing was achieved upon treatment of the cells with 5-azacytidine, which resulted in the demethylation of the reporter gene copies. We show that expression of a cDNA for the human p150 CAF-1 subunit harboring 5′ truncations, but not that of a cDNA encoding the full-length p150 CAF-1 subunit, increases by more than 500-fold the frequency at which transcriptional silencing of the reporter gene copies is reversed in these cells. Reversal of gene silencing is dependent upon expression of a truncated protein, possibly acting as a dominant negative mutant of the wild-type CAF-1, is associated with alterations in chromatin structure as measured by an endonuclease sensitivity assay and is not associated with detectable changes in the methylation status of the silenced genes. These results suggest that the role of CAF-1 in the epigenetic control of gene expression has been conserved between yeast and mammals, despite the lack of DNA methylation in yeast chromatin.

scholarly journals Viroids as a Tool to Study RNA-Directed DNA Methylation in Plants

Cells ◽  
2021 ◽  
Vol 10 (5) ◽  
pp. 1187
Author(s):  
Michael Wassenegger ◽  
Athanasios Dalakouras
Keyword(s):  
Dna Methylation ◽  
Rna Interference ◽  
Gene Silencing ◽  
Plant Cells ◽  
Transcriptional Gene Silencing ◽  
Rnai Machinery ◽  
Double Stranded Rna ◽  
Post Transcriptional Gene Silencing ◽  
Cumulative Amount

Viroids are plant pathogenic, circular, non-coding, single-stranded RNAs (ssRNAs). Members of the Pospiviroidae family replicate in the nucleus of plant cells through double-stranded RNA (dsRNA) intermediates, thus triggering the host’s RNA interference (RNAi) machinery. In plants, the two RNAi pillars are Post-Transcriptional Gene Silencing (PTGS) and RNA-directed DNA Methylation (RdDM), and the latter has the potential to trigger Transcriptional Gene Silencing (TGS). Over the last three decades, the employment of viroid-based systems has immensely contributed to our understanding of both of these RNAi facets. In this review, we highlight the role of Pospiviroidae in the discovery of RdDM, expound the gradual elucidation through the years of the diverse array of RdDM’s mechanistic details and propose a revised RdDM model based on the cumulative amount of evidence from viroid and non-viroid systems.

Sign in / Sign up

Export Citation Format

Share Document