This allows new insights into RPE autofluorescence patterns.”
“The trithorax (trxG) and Polycomb (PcG) group proteins recognize and propagate inheritable patterns of gene expression through a poorly understood epigenetic mechanism. A distinguishing feature of see more these proteins is the presence of a 130-amino-acid methyltransferase domain (SET), which catalyzes the methylation of histones. It is still not clear how SET proteins distinguish gene expression states, how they are targeted, or what regulates their substrate specificity. Many SET domain-containing proteins

show robust activity on core histones but relatively weak activity on intact nucleosomes, their physiological substrate. Here, we examined the binding of two SET domain-containing proteins, ALL1 and SET7, to chromatin substrates. The SET domains from these proteins bind and methylate intact nucleosomes poorly but can recognize disrupted nucleosomal structures associated learn more with transcribed chromatin. Interestingly, the remodeling of dinucleosomes by the ISWI class of ATP-dependent chromatin remodeling enzymes stimulated the binding of SET domains to chromatin and the methylation of H3 within the nucleosome. Unexpectedly, dinucleosomes remodeled by SWI/SNF were poor substrates. Thus,

SET domains can distinguish nucleosomes altered by these two classes of remodeling enzymes. Our study reveals novel insights into the mechanism of how SET domains recognize different chromatin states and specify histone methylation at active loci.”
“Activation of I-Kr Impairs Conduction. Introduction: The hERG (Kv11.1) LDN-193189 clinical trial potassium channel underlies cardiac I-Kr and is important for cardiac repolarization.

Recently, hERG agonists have emerged as potential antiarrhythmic drugs. As modulation of outward potassium currents has been suggested to modulate cardiac conduction, we tested the hypothesis that pharmacological activation of I-Kr results in impaired cardiac conduction.\n\nMethods and Results: Cardiac conduction was assessed in Langendorff-perfused guinea pig hearts. Application of the hERG agonist NS3623 (10 mu M) prolonged the QRS rate dependently. A significant prolongation (16 +/- 6%) was observed at short basic cycle length (BCL 90 ms) but not at longer cycle lengths (BCL 250 ms). The effect could be reversed by the I-Kr blocker E4031 (1 mu M). While partial I-Na inhibition with flecainide (1 mu M) alone prolonged the QRS (34 +/- 3%, BCL 250 ms), the QRS was further prolonged by 19 +/- 2% when NS3623 was added in the presence of flecainide. These data suggest that the effect of NS3623 was dependent on sodium channel availability. Surprisingly, in the presence of the voltage sensitive dye di-4-ANEPPS a similar potentiation of the effect of NS3623 was observed. With di-4-ANEPPS, NS3623 prolonged the QRS significantly (26 +/- 4%, BCL 250 ms) compared to control with a corresponding decrease in conduction velocity.