Gradual and oriented B-Z transition in 5'-untranscribed region of mouse ribosomal DNA.
The structural transition of an alternating purine-pyrimidine sequence (CG)5(TG)28) from the 5'-untranscribed region of the mouse ribosomal DNA was analyzed by two-dimensional gel electrophoresis and chemical probes. The repeat undergoes a supercoil-dependent gradual and oriented B-Z transition. At a threshold level of negative supercoiling, a limited region of the repeat encompassing the (CG)5 motif converts cooperatively into Z-DNA. As the superhelical stress increases, the Z-structure propagates along the remaining part of the repeat by successive transitions until the full-length sequence is converted. By in situ OsO4 probing experiments, we show also that this (TG)n-containing repeat adopts the Z-structure in Escherichia coli.
Albert
A C
AC
Centre de Biophysique Moléculaire, CNRS, Orléans, France.
Roman
A M
AM
Bouche
G
G
Leng
M
M
Rahmouni
A R
AR
D000079:Acetaldehyde / Q000031:analogs & derivatives / Q000494:pharmacology; D000818:Animals; D001482:Base Composition; D001483:Base Sequence; D004269:DNA, Bacterial / Q000737:chemistry; D004274:DNA, Recombinant / Q000737:chemistry / Q000187:drug effects; D004275:DNA, Ribosomal / Q000737:chemistry* / Q000187:drug effects; D004047:Diethyl Pyrocarbonate / Q000494:pharmacology; D015180:Electrophoresis, Gel, Two-Dimensional; D004926:Escherichia coli / Q000737:chemistry; D019811:Hydroxylamine; D006898:Hydroxylamines / Q000494:pharmacology; D051379:Mice; D008958:Models, Molecular; D015335:Molecular Probes; D008969:Molecular Sequence Data; D009690:Nucleic Acid Conformation; D009993:Osmium Tetroxide / Q000494:pharmacology; D012091:Repetitive Sequences, Nucleic Acid
D004269:DNA, Bacterial; D004274:DNA, Recombinant; D004275:DNA, Ribosomal; D006898:Hydroxylamines; D015335:Molecular Probes; D019811:Hydroxylamine; C004656:chloroacetaldehyde; D000079:Acetaldehyde; D004047:Diethyl Pyrocarbonate; D009993:Osmium Tetroxide