Purification, cloning, and RXR identity of the HeLa cell factor with which RAR or TR heterodimerizes to bind target sequences efficiently

Cell. 1992 Jan 24;68(2):377-95. doi: 10.1016/0092-8674(92)90478-u.


We have purified and cloned a HeLa cell nuclear protein that strongly stimulates binding of retinoic acid and thyroid hormone receptors (RARs and TRs) to response elements. The purified protein is a human retinoid X receptor beta (hRXR beta). Three murine members of the RXR family (mRXR alpha, beta, and gamma) have also been cloned, and their interactions with RARs and TRs have been investigated. Under conditions where RAR, RXR, and TR bound poorly as homodimers to various response elements, strongly cooperative RAR-RXR and TR-RXR binding was observed. The binding efficiency was dependent on the sequence, relative orientation, and spacing of the repeated motifs of response elements. We show also that unstable RAR-RXR heterodimers were formed in solution, and that C-terminal sequences and the DNA-binding domains of both receptors were required for efficient formation of stable heterodimers on response elements. These findings suggest a convergence of the signaling pathways of some members of the nuclear receptor superfamily.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Base Sequence
  • Binding Sites
  • Carrier Proteins / metabolism*
  • Cloning, Molecular
  • DNA / metabolism*
  • HeLa Cells
  • Humans
  • Macromolecular Substances
  • Molecular Sequence Data
  • Nuclear Proteins / genetics
  • Nuclear Proteins / isolation & purification
  • Nuclear Proteins / metabolism
  • Precipitin Tests
  • Receptors, Cell Surface / genetics
  • Receptors, Cell Surface / isolation & purification
  • Receptors, Cell Surface / metabolism*
  • Receptors, Retinoic Acid
  • Receptors, Thyroid Hormone / metabolism*
  • Regulatory Sequences, Nucleic Acid / genetics
  • Regulatory Sequences, Nucleic Acid / physiology
  • Repetitive Sequences, Nucleic Acid / genetics
  • Repetitive Sequences, Nucleic Acid / physiology
  • Retinoid X Receptors
  • Signal Transduction
  • Transcription Factors*
  • Tretinoin / metabolism*


  • Carrier Proteins
  • Macromolecular Substances
  • Nuclear Proteins
  • Receptors, Cell Surface
  • Receptors, Retinoic Acid
  • Receptors, Thyroid Hormone
  • Retinoid X Receptors
  • Transcription Factors
  • Tretinoin
  • DNA

Associated data

  • GENBANK/M84817
  • GENBANK/M84818
  • GENBANK/M84819
  • GENBANK/M84820
  • GENBANK/S72766
  • GENBANK/S72767
  • GENBANK/S72768
  • GENBANK/S72769
  • GENBANK/S72771
  • GENBANK/X63098