A novel sequence-specific DNA binding protein which interacts with three regularly spaced direct repeats of the CCCTC-motif in the 5'-flanking sequence of the chicken c-myc gene.
Oncogene
; 5(12): 1743-53, 1990 Dec.
Article
em En
| MEDLINE
| ID: mdl-2284094
ABSTRACT
The chicken c-myc 5'-flanking sequence has previously been shown to bind multiple proteins present in undifferentiated and differentiated red blood cells. In this report the protein binding to one specific region within a hypersensitive site approximately 200 base pairs upstream of the start of transcription has been analysed in detail. Using a combination of a modified agarose gel retardation assay with O-phenanthroline-copper footprinting in situ, missing contact point and methylation interference techniques, two proteins were found to bind to overlapping sequences within 180-230 bp upstream of the start of transcription. One protein resembles the transcription factor Sp1, the other is a protein which binds to three regularly spaced repeats of the core sequence CCCTC. This CCCTC-binding factor was termed CTCF. It requires additional sequences outside the three recognition motifs for tight binding. CTCF was purified to near homogeneity by sequence-specific DNA chromatography. The approximate molecular weight of the CTCF was estimated to be 130,000. Removal of 110 bp sequence binding both CTCF and Sp1-like proteins leads to a 4 to 8-fold increase in transcription of stably transfected c-myc fusion constructs in chicken embryonic fibroblasts, suggesting that the CTCF is likely to be one of multiple nuclear factors involved in the transcriptional regulation of the chicken c-myc gene.
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Base de dados:
MEDLINE
Assunto principal:
Timina
/
DNA
/
Sequências Repetitivas de Ácido Nucleico
/
Genes myc
/
Citosina
/
Proteínas de Ligação a DNA
Limite:
Animals
Idioma:
En
Ano de publicação:
1990
Tipo de documento:
Article