CTCF-Induced Circular DNA Complexes Observed by Atomic Force Microscopy.

摘要: The CTCF protein has emerged as a key architectural involved in genome organization. Although hypothesized to initiate DNA looping, direct evidence of CTCF-induced loop formation is still missing. Several studies have shown that the 11 zinc finger (11 ZF) domain actively binding. We here use atomic force microscopy examine effect ZF comprising residues 266-579 CTCF) and 3 402-494 (6-8 human on morphology. Our results show both domains alter architecture from relaxed morphology observed control samples compact circular complexes, meshes, networks, offering important insights into multivalent character domain. Atomic images reveal quasi-circular DNA/CTCF which are destabilized upon replacing by 6-8 domain, highlighting role motif formation. Intriguingly, complexes dominated non-specific binding, whereby contour length height profiles suggest single molecule twice wrapped around protein.