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Updated: May 28, 2026

Single-molecule Imaging of Gene Regulation In vivo Using Cotranslational Activation by Cleavage (CoTrAC)
11:31

Single-molecule Imaging of Gene Regulation In vivo Using Cotranslational Activation by Cleavage (CoTrAC)

Published on: March 15, 2013

Cotranscriptional effect of a premature termination codon revealed by live-cell imaging

Valeria de Turris1, Pamela Nicholson, Rodolfo Zamudio Orozco

  • 1Albert Einstein College of Medicine, Bronx, New York 10461, USA.

RNA (New York, N.Y.)
|October 27, 2011
PubMed

Insights

Nonsense-mediated mRNA decay (NMD) retains faulty transcripts with premature translation termination codons (PTCs) at the transcription site. This retention, dependent on UPF1 and SMG6, involves unspliced RNAs, suggesting a novel regulatory mechanism.

Area of Science:

  • Molecular Biology
  • Cell Biology
  • Genetics

Background:

  • Nonsense-mediated mRNA decay (NMD) is a crucial surveillance pathway in eukaryotes.
  • NMD eliminates aberrant mRNAs containing premature translation termination codons (PTCs).
  • The precise mechanisms regulating NMD, especially at the transcription site, remain incompletely understood.

Purpose of the Study:

  • To investigate the kinetics of mRNA synthesis and release at the transcription site.
  • To determine the fate of premature translation termination codon-containing (PTC+) transcripts.
  • To elucidate the role of NMD factors in the regulation of PTC+ transcripts.

Main Methods:

  • Live-cell imaging techniques were employed to monitor mRNA dynamics.
  • Fluorescence recovery after photobleaching (FRAP) and photoconversion analyses were used.
  • Chromatin immunoprecipitation (ChIP) assays were performed to assess protein-DNA interactions.

Main Results:

  • PTC+ transcripts were specifically retained at the transcription site.
  • The retained PTC+ transcripts were predominantly unspliced.
  • Depletion of UPF1 and SMG6 led to the release of PTC+ transcripts from the transcription site.
  • UPF1 and SMG6 physically associated with both PTC+ and PTC- reporter genes in vivo.

Conclusions:

  • A novel mechanism regulates PTC+ transcripts at the transcription site.
  • RNA retention at the transcription site is a key step in the NMD pathway.
  • The NMD factors UPF1 and SMG6 play a critical role in this transcription site-associated regulation.

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