Functional analysis of a growth factor-responsive transcription factor complex.
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.
Hill
C S
CS
Transcription Laboratory, Imperial Cancer Research Fund, London, England.
Marais
R
R
John
S
S
Wynne
J
J
Dalton
S
S
Treisman
R
R
D016475:3T3 Cells; D000595:Amino Acid Sequence; D000818:Animals; D001426:Bacterial Proteins / Q000737:chemistry / Q000378:metabolism; D001483:Base Sequence; D004252:DNA Mutational Analysis; D004268:DNA-Binding Proteins / Q000737:chemistry / Q000378:metabolism*; D005786:Gene Expression Regulation / Q000187:drug effects*; D006133:Growth Substances / Q000494:pharmacology*; D051379:Mice; D008969:Molecular Sequence Data; D009687:Nuclear Proteins / Q000737:chemistry / Q000378:metabolism*; D010750:Phosphoproteins / Q000378:metabolism; D010766:Phosphorylation; D011401:Promoter Regions, Genetic; D011518:Proto-Oncogene Proteins; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D015682:Retroviridae Proteins, Oncogenic / Q000737:chemistry / Q000378:metabolism*; D012697:Serine Endopeptidases; D026362:Serum Response Factor; D013329:Structure-Activity Relationship; D014157:Transcription Factors; D014158:Transcription, Genetic / Q000187:drug effects*; D050807:ets-Domain Protein Elk-1; D000099160:LexA Repressor Protein
D001426:Bacterial Proteins; D004268:DNA-Binding Proteins; D006133:Growth Substances; D009687:Nuclear Proteins; D010750:Phosphoproteins; D011518:Proto-Oncogene Proteins; D011993:Recombinant Fusion Proteins; D015682:Retroviridae Proteins, Oncogenic; D012697:Serine Endopeptidases; D026362:Serum Response Factor; D014157:Transcription Factors; D050807:ets-Domain Protein Elk-1; D000099160:LexA Repressor Protein; C494113:Elk1 protein, mouse