Related Experiment Video
Updated: Apr 22, 2026
09:20
CRISPR-Mediated Reorganization of Chromatin Loop Structure
Published on: September 14, 2018
14.2K
R-loops induce repressive chromatin marks over mammalian gene terminators
Konstantina Skourti-Stathaki1, Kinga Kamieniarz-Gdula1, Nicholas J Proudfoot1
1Sir William Dunn School of Pathology, South Parks Road, University of Oxford, Oxford OX1 3RE, UK.
Nature
|October 9, 2014
Summary
R-loops, DNA-RNA hybrids, induce antisense transcription at gene termination sites. This triggers RNA interference, leading to repressive histone marks that reinforce RNA polymerase II pausing and promote gene termination.
Area of Science:
- Molecular Biology
- Epigenetics
- Gene Regulation
Background:
- R-loops are DNA-RNA hybrids formed during transcription.
- Previously considered transcriptional byproducts, R-loops are now known to have regulatory roles.
- R-loops are enriched at G-rich terminator elements, influencing RNA polymerase II pausing.
Purpose of the Study:
- To investigate the functional role of R-loops at gene termination sites.
- To elucidate the mechanism linking R-loops to epigenetic modifications and transcriptional termination.
Main Methods:
- Analysis of R-loop formation and associated epigenetic marks.
- Investigating the role of RNA interference pathway components (DICER, AGOs).
- Studying the impact on RNA polymerase II pausing and gene termination.
Main Results:
- R-loops induce antisense transcription at pause elements.
- Antisense transcripts generate double-stranded RNA, recruiting DICER and AGO proteins.
- This leads to H3K9me2 deposition and HP1γ recruitment, reinforcing Pol II pausing.
Conclusions:
- R-loops promote RNA-interference-dependent H3K9me2 formation at termination regions.
- R-loops contribute to a chromatin architecture defining gene termination sites.
- This mechanism regulates transcriptional termination in mammalian protein-coding genes.
Related Concept Videos
02:42Transcription Attenuation in Prokaryotes
14.5K
Transcriptional attenuation occurs when RNA transcription is prematurely terminated due to the formation of a terminator mRNA hairpin structure. Bacteria use these hairpins to regulate the transcription process and control the synthesis of several amino acids including histidine, lysine, threonine, and phenylalanine. Transcription attenuation takes place in the non-coding regions of mRNA.
There are several different mechanisms used to attenuate transcription. In ribosome mediated...
There are several different mechanisms used to attenuate transcription. In ribosome mediated...
14.5K
03:17Inheritance of Chromatin Structures
6.0K
Epigenetics is the study of inherited changes in a cell's phenotype without changing the DNA sequences. It provides a form of memory for the differential gene expression pattern to maintain cell lineage, position-effect variegation, dosage compensation, and maintenance of chromatin structures such as telomeres and centromeres. For example, the structure and location of the centromere on chromosomes are epigenetically inherited. Its functionality is not dictated or ensured by the underlying...
6.0K
02:25Spreading of Chromatin Modifications
8.0K
The histone proteins in the nucleosomes are post-translationally modified (PTM) to increase or decrease access to DNA. The commonly observed PTMs are methylation, acetylation, phosphorylation, and ubiquitination of lysine amino acids in the histone H3 tail region. These histone modifications have specific meaning for the cell. Hence, they are called "histone code". The protein complex involved in histone modification is termed as "reader-writer" complex.
Writers
The writer...
Writers
The writer...
8.0K
03:18Non-LTR Retrotransposons
12.4K
As the name suggests, non-LTR retrotransposons lack the long terminal repeats characteristic of the LTR retrotransposons. Additionally, both LTR and non-LTR retrotransposons use distinct mechanisms of mobilization. Non-LTR retrotransposons are further divided into two classes - Long interspersed nuclear elements (LINEs) and short interspersed nuclear elements (SINEs), both of which occur abundantly in most mammals, including humans. Some of the active non-LTR retrotransposons in humans are L1...
12.4K
01:52Eukaryotic Transcription Inhibitors
9.0K
Certain biochemical processes, such as embryonic development and cell growth regulation, depend on the repression of specific genes. DNA binding proteins known as eukaryotic transcription inhibitors regulate the repression of gene expression in eukaryotes. The presence of these inhibitors at the required location and time in the cell is triggered by the presence of hormones and additional signals from other cells.
Eukaryotic transcription inhibitors usually contain two distinct domains, a...
Eukaryotic transcription inhibitors usually contain two distinct domains, a...
9.0K
02:38Heterochromatin
12.0K
The extent of chromatin compaction can be studied by staining chromatin using specific DNA binding dyes. Under the microscope, the dense-compacted regions that take up more dye are called heterochromatin. Heterochromatin is further classified into two forms – constitutive heterochromatin and facultative heterochromatin.
Constitutive heterochromatin: It is a highly compact region of chromatin that is mostly concentrated in the centromere and telomere. Unlike euchromatin, the amino acid at...
Constitutive heterochromatin: It is a highly compact region of chromatin that is mostly concentrated in the centromere and telomere. Unlike euchromatin, the amino acid at...
12.0K