Mapping functional regions of the segment-specific transcription factor Krox-20.
Krox-20, a zinc finger transcription factor with similarity to Sp1, is likely to play an important role in the development of the vertebrate central nervous system. A knowledge of its molecular properties will help to understand its physiological functions. We have therefore performed a structure-function analysis of the protein to identify the regions involved in DNA-binding and transcriptional activation. Our data suggest that only the zinc fingers are required for high affinity, specific DNA-binding. Transcriptional activation was not affected by deletion of the C-terminal tail of the protein. In contrast, deletion of the N-terminal half, upstream of the zinc fingers, completely abolished transactivation without affecting DNA-binding or nuclear localization. Two transcriptional activation domains were identified in this region. They cooperate to establish full activity. They are rich in negatively-charged amino acids and are therefore may constitute acidic activation domains. Comparative analysis of the amino acid sequences of several zinc finger proteins belonging to the Krox-20 subfamily indicates that they contain acidic regions at similar locations within their N-terminal region, suggesting that the functional organization of these proteins has been conserved during evolution.
Vesque
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Laboratoire de Génétique Moléculaire, CNRS D 1302, Ecole Normale Supérieure, Paris, France.
Charnay
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D000595:Amino Acid Sequence; D001483:Base Sequence; D015153:Blotting, Western; D002460:Cell Line; D004247:DNA / Q000378:metabolism; D004252:DNA Mutational Analysis; D004268:DNA-Binding Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D051767:Early Growth Response Protein 2; D004926:Escherichia coli / Q000235:genetics; D005455:Fluorescent Antibody Technique; D008969:Molecular Sequence Data; D011993:Recombinant Fusion Proteins / Q000235:genetics; D013329:Structure-Activity Relationship; D014157:Transcription Factors / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D014158:Transcription, Genetic / Q000235:genetics*; D016335:Zinc Fingers / Q000235:genetics*
D004268:DNA-Binding Proteins; D051767:Early Growth Response Protein 2; D011993:Recombinant Fusion Proteins; D014157:Transcription Factors; D004247:DNA