146 Oral - Chromatin
Saturday April 09, 8:30 AM - 8:45 AM

Authors:
Bright Amankwaa; Ryan Simmons; Ran An; Mariano Labrador

Affiliation: University of Tennessee, Knoxville

Keywords:
a. chromatin structure; f. insulators/boundary elements

Drosophila insulator proteins, which share genome architectural properties with their vertebrate counterparts, coalesce to form nuclear foci known as insulator bodies in response to osmotic stress. However, the mechanism behind the formation of these bodies remains unknown. Here, we identify signatures of liquid-liquid phase separation (LLPS) in insulator bodies. Mounting evidence implicates LLPS in the formation of membraneless organelles utilized for various biological functions, including genome structure and function. We show that insulator proteins have a high disorder tendency, assemble into insulator bodies in a scaffold-client dependent manner, have extensive fusion behavior, and show sensitivity to 1,6-hexanediol. Further, we characterize the Cohesin subunits Rad21 and Wapl as well as the phosphorylated version of the histone variant H2Av (γH2Av) as novel components of insulator body condensates. Our data suggest a concerted role of Cohesin, γH2Av and insulator proteins in the formation of insulator bodies and under physiological conditions. We propose a model whereby these architectural proteins modulate the 3D genome organization of Drosophila through LLPS.