Transcriptional activation through the tetrameric complex formation of E4TF1 subunits.
Transcription factor E4TF1 is composed of two types of subunit, an ets-related DNA binding protein, E4TF1-60, and its associated proteins with four tandemly repeated Notch-ankyrin motifs, E4TF1-53 and E4TF1-47. To determine the functional domains, we constructed various mutants of the subunits. E4TF1-60 bound to DNA as a monomer. The ets domain and its N-terminal flanking region were necessary to recognize the specific DNA sequence. The 48 amino acids at the E4TF1-60 C-terminus were required for interaction with the other type of subunit. E4TF1-53 and E4TF1-47 share the N-terminal 332 amino acids but differ at the C-termini. They interacted with E4TF1-60 through the N-terminal flanking region to form a heterodimer. E4TF1-53 dimerized with itself, whereas E4TF1-47 did not. The C-terminal region specific for E4TF1-53 was required for the dimerization. Therefore, heterodimers composed of E4TF1-53 and E4TF1-60 were further dimerized, resulting in the formation of a tetrameric complex, which stimulated transcription in vitro. Heterodimers of E4TF1-47 and E4TF1-60 weakly stimulated transcription in vitro. The results indicated that the tetrameric complex formation of E4TF1 subunits was necessary to activate transcription efficiently in vitro.
Sawada
J
J
Faculty of Bioscience and Biotechnology, Tokyo Institute of Technology, Yokohama, Japan.
Goto
M
M
Sawa
C
C
Watanabe
H
H
Handa
H
H
D001483:Base Sequence; D004247:DNA / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000378:metabolism; D051268:GA-Binding Protein Transcription Factor; D006367:HeLa Cells; D006801:Humans; D008969:Molecular Sequence Data; D011485:Protein Binding; D011487:Protein Conformation; D014157:Transcription Factors / Q000737:chemistry / Q000378:metabolism*; D015533:Transcriptional Activation
D004268:DNA-Binding Proteins; C079860:E4TF1 transcription factor; D051268:GA-Binding Protein Transcription Factor; D014157:Transcription Factors; D004247:DNA