[Regulatory protein factor CTCF interacts with a segment of the chicken c-myc oncogene promotor, capable of changing to a noncanonical conformation].
To identify the regions in the chicken c-myc promoter that are necessary for the binding of a nuclear trans-acting factor CTCF--the potential oncogene activator--we used a synthetic analog of the natural binding site that contains three correctly spaced CCCTC-repeats that are known to be involved in CTCF-binding. Gel retardation experiments failed to detect any CTCF-binding activity with this synthetic site. We conclude that GC-transversions made in the regions presumed to be invalid, do in fact interfere with the protein binding. The secondary structure analysis with S1-nuclease shows the presence of an unusual DNA conformation of the CTCF-binding site in the supercoiled plasmids, that can not be detected with the artificial construction. The precise mapping of S1 nuclease cleavage reveals several hypersensitive sites in the CCCTC-zone. Thus, an altered secondary structure may be functionally important for the protein recognition in vivo.
Tevosian
S G
SG
Gromova
E S
ES
Adler
V V
VV
Lobanenkov
V V
VV
D000818:Animals; D001483:Base Sequence; D002352:Carrier Proteins / Q000378:metabolism*; D002645:Chickens; D004247:DNA / Q000235:genetics; D004587:Electrophoresis, Agar Gel; D016259:Genes, myc; D008969:Molecular Sequence Data; D010957:Plasmids; D011401:Promoter Regions, Genetic; D011487:Protein Conformation; D013379:Substrate Specificity; D015534:Trans-Activators / Q000378:metabolism*
D002352:Carrier Proteins; D015534:Trans-Activators; D004247:DNA
Reguliatornyĭ belkovyĭ faktor CTCF vzaimodeĭstvuet s uchastkom promotora onkogena c-myc kur, sposobnym k perekhody v nekanonicheskuiu konformatsiiu.