Chromatin insulators and boundaries: effects on transcription and nuclear organization.

  title={Chromatin insulators and boundaries: effects on transcription and nuclear organization.},
  author={Tatiana I. Gerasimova and Victor G. Corces},
  journal={Annual review of genetics},
Chromatin boundaries and insulators are transcriptional regulatory elements that modulate interactions between enhancers and promoters and protect genes from silencing effects by the adjacent chromatin. Originally discovered in Drosophila, insulators have now been found in a variety of organisms, ranging from yeast to humans. They have been found interspersed with regulatory sequences in complex genes and at the boundaries between active and inactive chromatin. Insulators might modulate… 

Figures from this paper

Chromatin insulators.

Insulators are DNA elements that restrict the effects of long-range regulatory elements and like active chromatin hubs and silenced loci, insulators also cluster in the nucleus.

Genomic insulators: connecting properties to mechanism.

Endogenous gypsy insulators mediate higher order chromatin organization and repress gene expression in Drosophila

Experimental evidence is provided for a new role of intragenic Su(Hw) insulators in higher-order chromatin organization, repression of transcription, and RNA processing in polytene chromosomes.

Insulators and promoters: closer than we think

It is proposed that enhancer-blockers and silencing barrier-insulators might have evolved as specialized derivatives of promoters and that the two types of element use related mechanisms to mediate their distinct functions.

Chromatin Insulators: Master Regulators of the Eukaryotic Genome

The collection of work presented here addresses a central debate in the insulator field regarding the function of insulator bodies, exposing an unexpected link between their formation, osmotic stress and cell death, while disproving the prevailing hypothesis set forth over a decade ago.

Chromatin insulation by a transcriptional activator

Results from the assessment of the ability of a transcriptional activator to cause chromatin insulation are consistent with MTF acting as a chromatin insulator and imply that transcriptional activating elements can insulate active loci against chromatin repression.

Genomic insulators: connecting properties to mechanism Emily J Kuhnand Pamela K Geyer y

These processes will provide insights into prevention of inappropriate regulatory interactions, knowledge that can be applied to gene therapies, and emerging themes support connections between insulators, transcriptional activators and topological chromosomal domains.

Visualization of chromatin domains created by the gypsy insulator of Drosophila

The results suggest that the gypsy insulator might establish higher-order domains of chromatin structure and regulate nuclear organization by tethering the DNA to the nuclear matrix and creating chromatin loops.



Effects of cis arrangement of chromatin insulators on enhancer-blocking activity.

It is reported that the enhancer-blocking activity of the Drosophila suHw insulator is sensitive to insulator copy number and position, and insulators may modulate enhancers-promoter interactions by interacting with each other and facilitating the formation of chromatin loop domains.

Insulators and boundaries: versatile regulatory elements in the eukaryotic genome.

Not simply passive barriers, insulators are active participants in eukaryotic gene regulation and can be modulated by nearby regulatory elements, bound cofactors, or covalent modification of the DNA.

A chromatin insulator determines the nuclear localization of DNA.

The gypsy insulator of Drosophila affects chromatin structure in a directional manner.

It is shown that the gypsy insulator of Drosophila can affect chromatin structure, and insights into the mechanisms by which insulators affect enhancer-promoter interactions are offered.

Loss of insulator activity by paired Su(Hw) chromatin insulators.

It is shown that when two copies of the Su(Hw) insulator element are inserted between enhancer and promoter, insulator activity is neutralized and the enhancer-promoter interaction may instead be facilitated.

Genetic and molecular analysis of the gypsy chromatin insulator of Drosophila.

Two proteins have been identified that bind gypsy insulator sequences and are responsible for their effects on transcription and these effects seem to be modulated by changes in chromatin structure.

The role of insulator elements in defining domains of gene expression.

  • P. Geyer
  • Physics, Biology
    Current opinion in genetics & development
  • 1997

Polycomb and Trithorax Group Proteins Mediate the Function of a Chromatin Insulator

The boundaries of the silenced HMR domain in Saccharomyces cerevisiae.

The chromosomes of eukaryotes are organized into structurally and functionally discrete domains that provide a mechanism to compact the DNA as well as delineate independent units of gene activity. It

Modulation of enhancer-promoter interactions by insulators in the Drosophila embryo.

It is demonstrated that both insulators block the interaction of defined even-skipped (eve) stripe enhancers when positioned between the enhancer and the target promoter, suggesting that insulators might not be restricted to the functional isolation of neighbouring genetic loci and might function as flexible regulatory elements that modulate enhancer-promoter interactions within complex promoters and complex genetic locu.