Zinc Cluster Proteins Leu3p and Uga3p Recognize Highly Related but Distinct DNA Targets

Members of the family of fungal zinc cluster DNA-binding proteins possess 6 highly conserved cysteines that bind to two zinc atoms forming a structure (Zn 2 Cys 6 ) that is required for recognition of specific DNA sequences. Many zinc cluster proteins have been shown to bind as homodimers to a pair...

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Bibliographic Details
Published in:The Journal of biological chemistry 1998-07, Vol.273 (28), p.17463-17468
Main Authors: Noel, J, Turcotte, B
Format: Article
Language:English
Subjects:
Base Sequence
DNA Primers
DNA, Recombinant - metabolism
DNA-Binding Proteins - genetics
DNA-Binding Proteins - metabolism
Fungal Proteins - genetics
Fungal Proteins - metabolism
Mutagenesis, Site-Directed
Protein Binding
Saccharomyces cerevisiae Proteins
Trans-Activators - genetics
Trans-Activators - metabolism
Transcription Factors - genetics
Transcription Factors - metabolism
Zinc Fingers
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Summary:Members of the family of fungal zinc cluster DNA-binding proteins possess 6 highly conserved cysteines that bind to two zinc atoms forming a structure (Zn 2 Cys 6 ) that is required for recognition of specific DNA sequences. Many zinc cluster proteins have been shown to bind as homodimers to a pair of CGG triplets oriented either as direct (CGG N X CGG), inverted (CGG N X CCG), or everted repeats (CCG N X CGG), where N indicates nucleotides. Variation in the spacing between the CGG triplets also contributes to the diversity of sites recognized. For example, Leu3p binds to the everted sequence CCG N4 CGG with a strict requirement for a 4-base pair spacing. Here, we show that another member of the family, Uga3p, recognizes the same DNA motif as Leu3p. However, these transcription factors have distinct DNA targets. We demonstrate that additional specificity of binding is provided by nucleotides located between the two everted CGG triplets. Altering the 4 nucleotides between to the two everted CGG triplets switches the specificity from a Uga3p site to a Leu3p site in both in vitro and in vivo assays. Thus, our results identify a new mechanism that expands the repertoire of DNA targets of the family of zinc cluster proteins. These experiments provide a model for discrimination between targets of zinc cluster proteins.
ISSN:0021-9258
1083-351X
DOI:10.1074/jbc.273.28.17463