Abstract
Serum response factor (SRF) forms a ternary complex at the c-fos serum response element (SRE) with an accessory factor, Elk-1. We constructed altered-binding specificity derivatives of SRF and Elk-1 that form a ternary complex at a mutated, inactive SRE; like Elk-1, the Elk-1 variant only binds its target as part of a ternary complex with SRF. Simultaneous expression of these SRF and Elk-1 derivatives restores serum-regulated activity to the mutated SRE in transfected cells. Efficient transcriptional activation is dependent on the regulated phosphorylation of Elk-1 C-terminal MAP kinase sites and requires the C-terminal sequences of SRF as well as SRF sequences that mediate ternary complex formation. These experiments provide direct evidence that SRF and Elk-1 functionally cooperate in the ternary complex at the SRE to regulate transcription.
MeSH terms
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3T3 Cells
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Amino Acid Sequence
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Animals
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Bacterial Proteins / chemistry
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Bacterial Proteins / metabolism
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Base Sequence
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DNA Mutational Analysis
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DNA-Binding Proteins / chemistry
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DNA-Binding Proteins / metabolism*
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Gene Expression Regulation / drug effects*
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Growth Substances / pharmacology*
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Mice
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Molecular Sequence Data
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Nuclear Proteins / chemistry
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Nuclear Proteins / metabolism*
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Phosphoproteins / metabolism
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Phosphorylation
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Promoter Regions, Genetic
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Proto-Oncogene Proteins*
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Recombinant Fusion Proteins / metabolism
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Retroviridae Proteins, Oncogenic / chemistry
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Retroviridae Proteins, Oncogenic / metabolism*
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Serine Endopeptidases*
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Serum Response Factor
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Structure-Activity Relationship
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Transcription Factors*
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Transcription, Genetic / drug effects*
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ets-Domain Protein Elk-1
Substances
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Bacterial Proteins
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DNA-Binding Proteins
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Elk1 protein, mouse
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Growth Substances
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LexA protein, Bacteria
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Nuclear Proteins
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Phosphoproteins
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Proto-Oncogene Proteins
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Recombinant Fusion Proteins
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Retroviridae Proteins, Oncogenic
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Serum Response Factor
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Transcription Factors
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ets-Domain Protein Elk-1
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Serine Endopeptidases