The process of transcriptional elongation by RNA polymerase II (RNAPII) in a chromatin context involves a large number of crucial factors. Spn1 is a highly conserved protein encoded by an essential gene and is known to interact with RNAPII and the histone chaperone Spt6. Spn1 negatively regulates the ability of Spt6 to interact with nucleosomes, but the chromatin binding properties of Spn1 are largely unknown.
View Article and Find Full Text PDFLinker histones H1 are ubiquitous chromatin proteins that play important roles in chromatin compaction, transcription regulation, nucleosome spacing and chromosome spacing. H1 function in DNA and chromatin structure stabilization is well studied and established. The current paradigm of linker histone mode of function considers all other cellular roles of linker histones to be a consequence from H1 chromatin compaction and repression.
View Article and Find Full Text PDFCore histone octamers that are repetitively spaced along a DNA molecule are called nucleosomal arrays. Nucleosomal arrays are obtained in one of two ways: purification from in vivo sources, or reconstitution in vitro from recombinant core histones and tandemly repeated nucleosome positioning DNA. The latter method has the benefit of allowing for the assembly of a more compositionally uniform and precisely positioned nucleosomal array.
View Article and Find Full Text PDFThe H1 linker histones are abundant chromatin-associated DNA-binding proteins. Recent evidence suggests that linker histones also may function through protein-protein interactions. To gain a better understanding of the scope of linker histone involvement in protein-protein interactions, we used a proteomics approach to identify H1-binding proteins in human nuclear extracts.
View Article and Find Full Text PDFMethyl CpG binding protein 2 (MeCP2) is a canonical intrinsically disordered protein (IDP), that is, it lacks stable secondary structure throughout its entire polypeptide chain. Because IDPs often have the propensity to become locally ordered, we tested whether full-length MeCP2 and its constituent domains would gain secondary structure in 2,2,2-trifluoroethanol (TFE), a cosolvent that stabilizes intramolecular hydrogen bonding in proteins. The α-helix, β-strand/turn, and unstructured content were determined as a function of TFE concentration by deconvolution of circular dichroism data.
View Article and Find Full Text PDFTIP49b (reptin) is an essential eukaryotic AAA+ ATPase involved in a variety of cellular processes, such as chromatin remodeling during double-strand break repair, transcriptional regulation, control of cell proliferation and small nucleolar RNA biogenesis. How it acts at the molecular level remains largely unknown. In the present study, we show that both human TIP49b and its yeast orthologue, Rvb2p, cooperatively bind single-stranded DNA as monomers.
View Article and Find Full Text PDF