Biological significance of unwinding capability of nuclear matrix-associating DNAs.
Matrix attachment regions (MARs) are thought to separate chromatin into topologically constrained loop domains. A MAR located 5' of the human beta-interferon gene becomes stably base-unpaired under superhelical strain, as do the MARs flanking the immunoglobulin heavy chain gene enhancer; in both cases a nucleation site exists for DNA unwinding. Concatemerized oligonucleotides containing the unwinding nucleation site exhibited a strong affinity for the nuclear scaffold and augmented SV40 promoter activity in stable transformants. Mutated concatemerized oligonucleotides resisted unwinding, showed weak affinity for the nuclear scaffold, and did not enhance promoter activity. These results suggest that the DNA feature capable of relieving superhelical strain is important for MAR functions.
Bode
J
J
Gesellschaft für Biotechnologische Forschung, mbH, Genetik von Eukaryoten, Mascheroder Weg 1, Braunschweig-Stöckheim, Federal Republic of Germany.
Kohwi
Y
Y
Dickinson
L
L
Joh
T
T
Klehr
D
D
Mielke
C
C
Kohwi-Shigematsu
T
T
D001483:Base Sequence; D004247:DNA / Q000187:drug effects / Q000235:genetics* / Q000302:isolation & purification; D004591:Electrophoresis, Polyacrylamide Gel; D004742:Enhancer Elements, Genetic; D006801:Humans; D006834:Hydrazines / Q000494:pharmacology; D007143:Immunoglobulin Heavy Chains / Q000235:genetics*; D016899:Interferon-beta / Q000235:genetics*; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D015530:Nuclear Matrix / Q000502:physiology; D009838:Oligodeoxyribonucleotides; D010957:Plasmids; D015183:Restriction Mapping; D013463:Sulfuric Acid Esters; D014158:Transcription, Genetic
D006834:Hydrazines; D007143:Immunoglobulin Heavy Chains; D009838:Oligodeoxyribonucleotides; D013463:Sulfuric Acid Esters; C029424:hydrazine; D016899:Interferon-beta; D004247:DNA; C007482:dimethyl sulfate