title: A long polypyrimidine/polypurine tract induces an altered DNA conformation on the 3' coding region of the adjacent myosin heavy chain gene.
abstract: A long (147 base pairs), natural A.T rich polypyrimidine/polypurine tract has been found 55 base pairs downstream of a chicken embryonic myosin heavy chain (MHC) gene. Analysis at the nucleotide level of nicks induced by S1 and Neurospora crassa nucleases indicate that this long interrupted polypyrimidine/polypurine tract exists in an alternate DNA structure in vitro at pH 4.5 and pH 7.5 in both supercoiled and linear plasmid DNA. The polypyrimidine/polypurine tract induces this alternate structure upon at least 200 base pairs of its 5' flanking DNA, and thus extends into the 3' coding and non-coding regions of the neighboring MHC gene. The different nicking patterns induced by the nucleases S1 and N. crassa on each strand of this alternate structure suggests that the polypyrimidine/polypurine tract may form heteronomous DNA. When this long polypyrimidine/polypurine tract is present in a supercoiled plasmid at low pH, a new and as yet undefined S1 hypersensitive DNA alteration was detected near the center of this tract.
authors: Department of Molecular and Cell Biology, University of Connecticut, Storrs 06268.
authors: J G
authors: JG
authors: McCarthy
authors: S M
authors: SM
authors: Heywood
mesh_terms: D000818:Animals; D001483:Base Sequence; D002642:Chick Embryo; D004274:DNA, Recombinant; D004278:DNA, Superhelical; D005796:Genes; D008969:Molecular Sequence Data; D009218:Myosins / Q000235:genetics*; D009690:Nucleic Acid Conformation
chemical_list: D004274:DNA, Recombinant; D004278:DNA, Superhelical; D009218:Myosins