PU.1 and a TTTAAA element in the myeloid defensin-1 promoter create an operational TATA box that can impose cell specificity onto TFIID function.
Defensins are major components of a peptide-based, antimicrobial system in human neutrophils. While packed with peptide, circulating cells contain no defensin-1 (def1) transcripts, except in some leukemia patients and in derivative promyelocytic leukemia cell lines. Expression is modulated by serum factors, mediators of inflammation, and kinase activators and inhibitors, but the underlying mechanisms are not fully understood. A minimal def1 promoter drives transcription in HL-60 cells under control of PU.1 and a def1-binding protein ("D1BP"), acting through, respectively, proximal (-22/-19) and distal (-62/-59) GGAA elements. In this study, we identify D1BP, biochemically and functionally, as GA-binding protein (GABP)alpha/GABPbeta. Whereas GABP operates as an essential upstream activator, PU.1 assists the flanking "TTTAAA" element (-32/-27), a "weak" but essential TATA box, to bring TBP/TFIID to the transcription start site. PU.1 thus imparts a degree of cell specificity to the minimal promoter and provides a potential link between a number of signaling pathways and TFIID. However, a "strong" TATA box ("TATAAA") eliminates the need for the PU.1 binding site and for PU.1, but not for GABP. As GABP is widely expressed, a strong TATA box thus alleviates promyelocytic cell specificity of the def1 promoter. These findings suggest how the myeloid def1 promoter may have evolutionarily acquired its current properties.
Yaneva
Mariana
M
Molecular Biology Program, Memorial Sloan-Kettering Cancer Center, and Weill Graduate School of Medical Sciences, Cornell University, New York, NY 10021, USA.
Kippenberger
Serena
S
Wang
Nan
N
Su
Qin
Q
McGarvey
Margaret
M
Nazarian
Arpi
A
Lacomis
Lynne
L
Erdjument-Bromage
Hediye
H
Tempst
Paul
P
D024506:5' Flanking Region / Q000235:genetics; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D001665:Binding Sites / Q000235:genetics; D002460:Cell Line; D045744:Cell Line, Tumor; D023082:Defensins / Q000235:genetics / Q000378:metabolism*; D018900:Dinucleotide Repeats; D004331:Drosophila melanogaster / Q000235:genetics / Q000378:metabolism; D018922:HL-60 Cells; D006801:Humans; D008969:Molecular Sequence Data; D022423:Myeloid Cells / Q000378:metabolism* / Q000502:physiology; D011401:Promoter Regions, Genetic; D011485:Protein Binding / Q000235:genetics; D011518:Proto-Oncogene Proteins / Q000502:physiology*; D050783:Proto-Oncogene Proteins c-ets / Q000378:metabolism; D011994:Recombinant Proteins / Q000378:metabolism; D016385:TATA Box / Q000502:physiology*; D035181:TATA-Box Binding Protein / Q000302:isolation & purification / Q000378:metabolism; D015534:Trans-Activators / Q000502:physiology*; D035362:Transcription Factor TFIID / Q000378:metabolism / Q000502:physiology*; D000099232:Proto-Oncogene Protein Spi-1
D023082:Defensins; D011518:Proto-Oncogene Proteins; D050783:Proto-Oncogene Proteins c-ets; D011994:Recombinant Proteins; D035181:TATA-Box Binding Protein; D015534:Trans-Activators; D035362:Transcription Factor TFIID; D000099232:Proto-Oncogene Protein Spi-1