title: Methylation sensitive protein binding to an intragenic active X-specific methylated region in the M. robustus Hprt gene.
abstract: An intragenic region of the wallaroo (Macropus robustus) hypoxanthine phosphoribosyltransferase gene which contains three active X-specific methylated cytosines was examined for protein(s) binding. In vitro DNase I footprinting of unmethylated DNA identified three footprints, one of which (footprint I) contained two of the known differentially methylated sites (a HpaII and a HhaI site). Methylation of the footprint I HpaII site only, abolished the formation of several, specific DNA-protein complexes in mobility shift assays. UV cross-linking experiments indicated that polypeptides involved in the methylation sensitive interactions with footprint I had molecular weights ranging from 72 to 48 kDa. Analogous results were obtained with nuclear extracts from both eutherian and metatherian cells, indicating that these proteins are conserved. We suggest that the binding of these proteins to the inactive X may play some role in gene silencing, with the active gene being protected from this effect by methylation of the binding site.
authors.affiliation: Department of Cell and Molecular Biology, University of Technology Sydney, New South Wales, Australia.
authors.forename: S
authors.initials: S
authors.lastname: Chong
authors.forename: A A
authors.initials: AA
authors.lastname: Piper
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D019175:DNA Methylation; D008040:Genetic Linkage; D007041:Hypoxanthine Phosphoribosyltransferase / Q000235:genetics*; D008969:Molecular Sequence Data; D011485:Protein Binding / Q000235:genetics; D016415:Sequence Alignment; D014960:X Chromosome
chemical_list: D007041:Hypoxanthine Phosphoribosyltransferase