The nuclear matrix associating protein HNRNPU functions as a key regulator of 3D genome architecture [Hi-C]

Higher-order chromatin conformation plays critical role in regulating gene expression and biological development, here we show that HNRNPU, a nuclear matrix attachment factor, is a regulator of 3D genome architecture at multiple levels in mouse hepatocytes. We demonstrate that depletion of HNRNPU results into a global reorganization of nuclear bodies and re-localization of chromatin towards nuclear periphery. Additionally, upon HNRNPU depletion, chromatin interactions between A-type (active) and B-type (inactive) compartments increase significantly but those among same types of compartments decrease significantly, which associate with global gene expression changes. While TADs remain largely invariant, both inter- and intra-TAD interactions increase significantly in A-type compartments but decrease in B-type compartments. Mechanically, HNRNPU complexes with structural proteins CTCF and RAD21; depletion of HNRNPU specifically weakens the bindings of RAD21 to the chromatin, which is highly correlated with the weakness of chromatin loops. Hi-C data in Ctrl and HNRNPU KD AML12 cells.