Definition of the DNA-binding specificity of TTF-1 homeodomain by chromatographic selection of binding sequences.
The homeodomain of the thyroid transcription factor-1 (TTF-1HD) shows a peculiar DNA-binding specificity, preferentially recognizing sequences having the 5'-CAAG-3' core motif. In order to detail the DNA-binding specificity of this protein, a TTF-1HD-Sepharose column chromatography was used. A sequential selection and amplification of sequences was performed. TTF-1HD binding activity for selected and unselected sequences was measured. The presence of the 5'-CAAG-3' core motif was necessary, but not sufficient, to obtain the maximal binding activity for TTF-1HD. However, several of the selected sequences do not contain the 5'-CAAG-3' core motif and are bound by TTF-1HD only 2-fold less with respect to sequences bound with the highest affinity. Therefore, these data indicate that TTF-1HD specifically recognizes a spectrum of sequences wider than previously determined.
Fabbro
D
D
Dipartimento di Scienze e Tecnologie Biomediche, Università di Udine, Italy.
Tell
G
G
Pellizzari
L
L
Leonardi
A
A
Pucillo
C
C
Lonigro
R
R
Damante
G
G
D001483:Base Sequence; D003001:Cloning, Molecular; D004247:DNA / Q000378:metabolism*; D017931:DNA Primers; D004926:Escherichia coli / Q000235:genetics; D018398:Homeodomain Proteins / Q000378:metabolism*; D008969:Molecular Sequence Data; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism*; D011485:Protein Binding; D000074482:Thyroid Nuclear Factor 1; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*
D017931:DNA Primers; D018398:Homeodomain Proteins; D009687:Nuclear Proteins; D000074482:Thyroid Nuclear Factor 1; D014157:Transcription Factors; D004247:DNA