Biochemical deconstruction and reconstruction of Nuclear Matrix reveals the layers of nuclear organization

Abstract

Nuclear Matrix (NuMat) is the fraction of the eukaryotic nucleus insoluble to detergents and high-salt extractions that manifests as a pan-nuclear fiber-granule network. NuMat consists of ribonucleoprotein complexes, members of crucial nuclear functional modules, and DNA fragments. Although NuMat captures the organization of non-chromatin nuclear space, very little is known about component organization within NuMat. To understand the organization of NuMat components, we subfractionated it with increasing concentrations of the chaotrope Guanidinium Hydrochloride (GdnHCl) and analyzed the proteomic makeup of the fractions. We observe that the solubilization of proteins at different concentrations of GdnHCl is finite and independent of the broad biophysical properties of the protein sequences. Looking at the extraction pattern of the Nuclear Envelope and Nuclear Pore Complex, we surmise that this fractionation represents easily-solubilized/loosely-bound and difficultly-solubilized/tightlybound components of NuMat.