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CSL ‐ DNA interactions, from thermodynamics to structure
Author(s) -
Kovall Rhett Allen,
Friedmann David Robert
Publication year - 2009
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.23.1_supplement.494.3
Subject(s) - dna , enhancer , transcription factor , transcription (linguistics) , binding site , dna binding site , computational biology , biology , promoter , chemistry , biophysics , genetics , gene , gene expression , linguistics , philosophy
Canonical Notch signaling ultimately results in changes in gene expression. The transcription factor CSL (CBF1, Su(H), Lag‐1) is a site‐specific DNA binding transcription factor that is central to the regulation of transcription from all Notch responsive genes. Additional regulation arises from DNA elements that contain a pair of CSL binding sites arranged in a head‐to‐head manner, as typified by the HES‐1 (Hairy and Enhancer of Split‐1) promoter. While the DNA consensus‐binding sequence of CSL has been identified and high‐resolution crystal structures of CSL bound to this site have been determined, there is a considerable gap in our understanding of the thermodynamics that define CSL‐DNA complexes. In particular, a quantitative description of the energetics that underlie CSL‐DNA interactions with the HES‐1 site is not available. The overall goal of this study is to thermodynamically and structurally characterize the interaction of CSL with DNA, including its interaction with the HES‐1 element, which contains both consensus and nonconsensus sites. Our calorimetry data suggests that CSL binding to DNA is an entropically driven reaction with a ~200 nM Kd. Our X‐ray structures of CSL bound to a nonconsensus DNA site reveal a number of structural differences when compared to CSL‐consensus DNA complexes. Research supported by a grant from the National Institutes of Health (R01 CA120199).