Abstract
PU.1 is a member of the Ets family of transcription factors and plays critical roles in the development of hematopoietic cells such as macrophages and B cells. To elucidate the molecular mechanism(s) underlying the regulation of PU.1 function, we screened for PU.1 interacting proteins using a yeast two-hybrid approach. As a result, a novel PU.1 binding factor, which we termed Pub, was isolated. The Pub protein has one B-box zinc finger domain, followed by a coiled-coil region and a B30.2-like domain, these features being characteristic of the tripartite motif (TRIM) family of protein. The PEST domain of PU.1 was found to interact with the N-terminal portion of Pub, a region that includes the TRIM which is considered to mediate protein-protein interactions. Northern blot and RT-PCR analyses demonstrated that Pub is predominantly expressed in hematopoietic tissues and cells where PU.1 is also expressed. Using a luciferase-based assay, we showed that Pub inhibited the transcriptional activity of PU.1. Moreover, the B-box zinc finger domain of Pub was critical for this inhibitory activity. These data suggest that Pub may be important in regulating the transcriptional activity of PU.1.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Amino Acid Sequence
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Animals
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Binding Sites
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Carrier Proteins / chemistry*
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Carrier Proteins / genetics
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Carrier Proteins / metabolism*
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DNA-Binding Proteins / chemistry*
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DNA-Binding Proteins / genetics
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DNA-Binding Proteins / metabolism*
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Gene Expression Regulation / physiology
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HeLa Cells
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Hematopoiesis / physiology*
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Humans
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Interferon Regulatory Factors
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Intracellular Signaling Peptides and Proteins
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Mice
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Molecular Sequence Data
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Protein Binding
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Protein Conformation
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Protein Structure, Tertiary
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Proto-Oncogene Proteins / chemistry*
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Proto-Oncogene Proteins / genetics
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Proto-Oncogene Proteins / metabolism*
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Sequence Alignment
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Trans-Activators / chemistry*
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Trans-Activators / genetics
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Trans-Activators / metabolism*
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Transcription Factors / chemistry
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Transcription Factors / genetics
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Transcription Factors / metabolism
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Transcriptional Activation / physiology*
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Tripartite Motif Proteins
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Two-Hybrid System Techniques
Substances
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Carrier Proteins
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DNA-Binding Proteins
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Interferon Regulatory Factors
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Intracellular Signaling Peptides and Proteins
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Proto-Oncogene Proteins
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TRIM14 protein, human
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Trans-Activators
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Transcription Factors
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Trim14 protein, mouse
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Tripartite Motif Proteins
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interferon regulatory factor-4
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proto-oncogene protein Spi-1