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Light-activated transcription and repression by using photocaged SERMs

Youheng Shi1, John T Koh

  • 1Department of Chemistry and Biochemistry, University of Delaware, Newark, DE 19716, USA.

Chembiochem : a European Journal of Chemical Biology
|June 3, 2004
PubMed

Insights

Researchers developed photocaged selective estrogen receptor modulators (SERMs) for light-controlled gene expression. These compounds offer precise temporal and spatial control over gene activity, advancing research into gene function.

Area of Science:

  • Molecular Biology
  • Genetics
  • Pharmacology

Background:

  • Gene spatiotemporal patterning is crucial for biological functions.
  • Photocaged ligands offer light-directed control over gene expression.
  • Nuclear receptors play key roles in gene regulation.

Purpose of the Study:

  • To evaluate photocaged analogues of selective estrogen receptor modulators (SERMs) for controlling gene expression patterning.
  • To investigate the light-directed actions of photocaged SERMs on estrogen receptor (ER) activity.
  • To explore the simultaneous control of transcription activation and repression using photocaged SERMs.

Main Methods:

  • Synthesis of photocaged hydroxytamoxifen (NB-Htam) and guanidine tamoxifen (NB-Gtam).
  • Evaluation of NB-Htam and NB-Gtam for antagonizing ER alpha- and ER beta-mediated transcription at estrogen response elements (EREs).
  • Assessment of transcription recovery rates upon SERM diffusion from cells.
  • Investigation of ER beta-mediated transcription activation at AP1 sites.

Main Results:

  • NB-Htam and NB-Gtam selectively antagonize ER alpha and ER beta transcription in response to light.
  • Intracellular Htam and Gtam induce transient transcriptional repression.
  • Transcription recovery rates for Htam and Gtam are faster than for tamoxifen aziridine (Taz), suggesting ligand off-rates/diffusion control duration.
  • Gtam activates ER beta-mediated transcription at AP1 sites.
  • Photocaged SERMs enable light-activated transcription and repression simultaneously.

Conclusions:

  • Photocaged SERMs provide precise light-directed control over gene expression.
  • Ligand off-rates and diffusion, rather than receptor turnover, dictate the duration of SERM action.
  • These tools allow for simultaneous light-activated transcription and repression, offering novel research capabilities.

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