Pub, a novel PU.1 binding protein, regulates the transcriptional activity of PU.1

Biochem Biophys Res Commun. 2003 Nov 14;311(2):351-60. doi: 10.1016/j.bbrc.2003.09.212.

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

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Binding Sites
  • Carrier Proteins / chemistry*
  • Carrier Proteins / genetics
  • Carrier Proteins / metabolism*
  • DNA-Binding Proteins / chemistry*
  • DNA-Binding Proteins / genetics
  • DNA-Binding Proteins / metabolism*
  • Gene Expression Regulation / physiology
  • HeLa Cells
  • Hematopoiesis / physiology*
  • Humans
  • Interferon Regulatory Factors
  • Intracellular Signaling Peptides and Proteins
  • Mice
  • Molecular Sequence Data
  • Protein Binding
  • Protein Conformation
  • Protein Structure, Tertiary
  • Proto-Oncogene Proteins / chemistry*
  • Proto-Oncogene Proteins / genetics
  • Proto-Oncogene Proteins / metabolism*
  • Sequence Alignment
  • Trans-Activators / chemistry*
  • Trans-Activators / genetics
  • Trans-Activators / metabolism*
  • Transcription Factors / chemistry
  • Transcription Factors / genetics
  • Transcription Factors / metabolism
  • Transcriptional Activation / physiology*
  • Tripartite Motif Proteins
  • Two-Hybrid System Techniques

Substances

  • Carrier Proteins
  • DNA-Binding Proteins
  • Interferon Regulatory Factors
  • Intracellular Signaling Peptides and Proteins
  • Proto-Oncogene Proteins
  • TRIM14 protein, human
  • Trans-Activators
  • Transcription Factors
  • Trim14 protein, mouse
  • Tripartite Motif Proteins
  • interferon regulatory factor-4
  • proto-oncogene protein Spi-1

Associated data

  • GENBANK/AB117644