Halotag: A novel reporter gene for positron emission tomography

Hao Hong, Hélène A. Benink, Yin Zhang, Yunan Yang, H. Tetsuo Uyeda, Jonathan W. Engle, Gregory W. Severin, Mark G. McDougall, Todd E. Barnhart, Dieter H. Klaubert, Robert J. Nickles, Frank Fan, Weibo Cai

Research output: Contribution to journalJournal articleResearchpeer-review


Among the many molecular imaging techniques, reporter gene imaging has been a dynamic area of re-search. The HaloTag protein is a modified haloalkane dehalogenase which was designed to covalently bind to syn-thetic ligands (i.e. the HaloTag ligands [HTL]). Covalent bond formation between the HaloTag protein and the chloroal-kane within the HTL occurs rapidly under physiological conditions, which is highly specific and essentially irreversible. Over the years, HaloTag technology has been investigated for various applications such as in vitro/in vivo imaging, protein purification/trafficking, high-throughput assays, among others. The goal of this study is to explore the use of the HaloTag protein as a novel reporter gene for positron emission tomography (PET) imaging. By attaching a HaloTag-reactive chloroalkane to 1, 4, 7-triazacyclononane-N, N', N''-triacetic acid (NOTA) through hydrophilic linkers, the re-sulting NOTA-conjugated HTLs were labeled with 64Cu and tested for PET imaging in living mice bearing 4T1-HaloTag-ECS tumors, which stably express the HaloTag protein on the cell surface. Significantly higher uptake of 64Cu-NOTA-HTL-S (which contains a short hydrophilic linker) in the 4T1-HaloTag-ECS than the non-HaloTag-expressing 4T1 tu-mors was observed, which demonstrated the HaloTag specificity of 64Cu-NOTA-HTL-S and warranted future investiga-tion of the HaloTag protein as a PET reporter gene.
Original languageEnglish
JournalAmerican Journal of Translational Research
Issue number4
Pages (from-to)392-403
Number of pages12
Publication statusPublished - 2011
Externally publishedYes


  • Medicine (all)
  • Cancer Research
  • Clinical Biochemistry
  • Molecular Medicine
  • Cancer
  • Cell tracking
  • Halotag
  • Molecular imaging
  • Positron emission tomography (PET)
  • Reporter gene
  • 1,4,7 triazacyclononane n,n',n'' triacetic acid halotag cu 64
  • alkyl chloride
  • haloalkane dehalogenase
  • hydrolase
  • radiopharmaceutical agent
  • unclassified drug
  • animal cell
  • animal experiment
  • animal model
  • article
  • breast cancer
  • cancer cell culture
  • drug distribution
  • female
  • halotag gene
  • in vitro study
  • in vivo study
  • mouse
  • nonhuman
  • positron emission tomography
  • reporter gene
  • Mus


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