Induction by torsional stress of an altered DNA conformation 5' upstream of the gene for a high mobility group protein from trout and specific binding to flanking sequences by the gene product HMG-T.
We have used enzymic and chemical probes to search for altered DNA conformations in the 5' flanking region of the gene for a high mobility group protein (HMG-T) from trout. This search was conducted in order to identify potential genetic elements that might be involved in the transcriptional control of the HMG-T gene. We identified, in supercoiled plasmid DNA molecules containing a 900 base pair insert of the 5' region of the gene, an S1-sensitive site situated within an (AT)12 sequence approximately 120 base pairs upstream from the start of the HMG-T gene. Chemical modification of supercoiled DNA with the single-strand-selective reagent bromoacetaldehyde was limited to a region coincident with the S1 nuclease site. T7 endonuclease I, a probe highly specific for four-way helical junctions, cleaved predominantly at the boundaries of the (AT)12 stretch. These data are most consistent with the interpretation that the (AT)12 sequence adopts a cruciform structure when torsionally stressed by negative supercoiling. DNase I footprinting analyses demonstrated that HMG-T protects two regions almost equidistant from the center of the (AT)12 sequence, indicating that HMG-T is a sequence-specific DNA binding protein.
Wright
J M
JM
Department of Medical Biochemistry, University of Calgary Health Sciences Centre, Alberta, Canada.
Dixon
G H
GH
D000818:Animals; D001483:Base Sequence; D003001:Cloning, Molecular; D004247:DNA / Q000235:genetics* / Q000378:metabolism / Q000648:ultrastructure; D004262:DNA Restriction Enzymes; D004278:DNA, Superhelical / Q000235:genetics; D005796:Genes; D005809:Genes, Regulator; D006609:High Mobility Group Proteins / Q000235:genetics* / Q000378:metabolism; D008969:Molecular Sequence Data; D009690:Nucleic Acid Conformation; D009710:Nucleotide Mapping; D011485:Protein Binding; D014158:Transcription, Genetic; D014337:Trout
D004278:DNA, Superhelical; D006609:High Mobility Group Proteins; D004247:DNA; D004262:DNA Restriction Enzymes