Helix-loop-helix transcriptional activators bind to a sequence in glucocorticoid response elements of retrovirus enhancers.
A family of nuclear proteins, designated SL3-3 enhancer factors 2 (SEF2), were found to interact with an Ephrussi box-like motif within the glucocorticoid response element in the enhancer of the murine leukemia virus SL3-3. Mutation of the DNA sequence decreased the basal enhancer activity in various cell lines. The important nucleotides for binding of SEF2 are conserved in most type C retroviruses. Various cell types displayed differences both in the sets of SEF2-DNA complexes formed and in their amounts. A cDNA which encoded a protein that interacted specifically with the SEF2-binding sequence was isolated from human thymocytes. The nucleotide sequence specificity of the recombinant protein, expressed in Escherichia coli, corresponded to that of at least one of the nuclear SEF2 proteins. Sequence analysis of the cDNA revealed that it belongs to the basic helix-loop-helix class of DNA-binding proteins. Several mRNA transcripts of different sizes were identified. Molecular analysis of cDNA clones revealed multiple related mRNA species containing alternative coding regions, which are most probably a result of differential splicing.
Department of Applied Cell and Molecular Biology, University of Umeå, Sweden.
B
B
Corneliussen
A
A
Thornell
B
B
Hallberg
T
T
Grundström
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D051778:Basic Helix-Loop-Helix Leucine Zipper Transcription Factors; D001665:Binding Sites; D015152:Blotting, Northern; D002460:Cell Line; D003001:Cloning, Molecular / Q000379:methods; D004268:DNA-Binding Proteins; D004742:Enhancer Elements, Genetic; D004926:Escherichia coli / Q000235:genetics; D006367:HeLa Cells; D006801:Humans; D009052:Leukemia Virus, Murine / Q000235:genetics*; D051379:Mice; D008969:Molecular Sequence Data; D008970:Molecular Weight; D009419:Nerve Tissue Proteins; D009687:Nuclear Proteins / Q000378:metabolism*; D009838:Oligodeoxyribonucleotides; D011061:Poly A / Q000032:analysis / Q000235:genetics; D012333:RNA, Messenger / Q000032:analysis / Q000235:genetics; D011965:Receptors, Glucocorticoid / Q000378:metabolism*; D012689:Sequence Homology, Nucleic Acid; D051820:TCF Transcription Factors; D015534:Trans-Activators / Q000378:metabolism*; D000073940:Transcription Factor 4; D058118:Transcription Factor 7-Like 2 Protein; D014157:Transcription Factors; D014158:Transcription, Genetic; D014162:Transfection
D051778:Basic Helix-Loop-Helix Leucine Zipper Transcription Factors; D004268:DNA-Binding Proteins; D009419:Nerve Tissue Proteins; D009687:Nuclear Proteins; D009838:Oligodeoxyribonucleotides; D012333:RNA, Messenger; D011965:Receptors, Glucocorticoid; D051820:TCF Transcription Factors; C532096:TCF4 protein, human; C544894:TCF7L2 protein, human; C090743:Tcf4 protein, mouse; C544895:Tcf7l2 protein, mouse; D015534:Trans-Activators; D000073940:Transcription Factor 4; D058118:Transcription Factor 7-Like 2 Protein; D014157:Transcription Factors; D011061:Poly A