High impact information on Insulator Elements

• Htz1 is enriched in these euchromatic regions and acts synergistically with a boundary element to prevent the spread of heterochromatin [1].
• Here we identify two CTCF-binding sites that flank the CTG repeat and form an insulator element between DMPK and SIX5 [2].
• These results support the model that Fab-7 functions as a domain boundary within the context of the bithorax complex, making Fab-7 one of the first boundary elements that is known to have an essential function in vivo [3].
• Prior studies of the DM1 locus have shown that the CTG repeats are a component of a CTCF-dependent insulator element and that repeat expansion results in conversion of the region to heterochromatin [4].
• The chicken beta-globin 5'HS4 insulator element acts as a barrier to the encroachment of chromosomal silencing [5].

Biological context of Insulator Elements

• Here we focus on the characterization of a moderately repeated 1.2 kb DNA sequence that encompasses boundary element 28 (BE28) [6].

Associations of Insulator Elements with chemical compounds

• Notably, there is a very strong constitutive focus of hyperacetylation at the 5' insulator element separating the globin locus from the folate receptor region, which suggests that this insulator element may harbor a high concentration of histone acetylases [7].
• We suggest that histone H3 modification at lysine 9 directly regulates chromatin condensation by recruiting MENT to chromatin in a fashion that is spatially constrained from active genes by gene boundary elements and histone hyperacetylation [8].
• Electrostatic potentials computed using a hybrid boundary element and finite difference nonlinear Poisson-Boltzmann approach [Boschitsch, A.H. and Fenley, M.O. (2004) J. Comput. Chem., 25, 935-955] revealed a region of exceptionally negative potential in the major groove surrounding the 2'-OH of the branch site adenosine [9].

Gene context of Insulator Elements

• Furthermore, the transcripts from each iab region are discrete and the transcripts do not spread across the insulator elements that delineate the iab regions [10].
• The first considers that Fab-7 functions as a boundary element that insulates iab-6 and iab-7 [11].
• The chicken beta-globin insulator element conveys chromatin boundary activity but not imprinting at the mouse Igf2/H19 domain [12].
• Recent studies have examined additional roles for RAP1 in heterochromatin boundary-element formation, creation of hotspots for meiotic recombination, and chromatin opening [13].
• In this report we show that both CTCF and the HS4 insulator element are incorporated in the matrix; HS4 incorporation depends on the presence of an intact CTCF-binding site [14].

Analytical, diagnostic and therapeutic context of Insulator Elements

• Simulation studies with a concentric spheres model and a more realistic boundary element model indicate that this method has several advantages, even if only a few EEG sensors are added to a MEG configuration [15].

References