Cytosine deaminase as a negative selective marker for Arabidopsis

Ranian J. Perera, Christian G. Linard, Ethan R. Signer

Research output: Contribution to journalArticlepeer-review


Cytosine deaminase (CD), produced by prokaryotes but not by higher eukaryotes including plants, deaminates cytosine to uracil. The enzyme likewise converts 5-fluorocytosine (5FC), which by itself is not toxic, to 5-fluorouracil (5FU), which is toxic. The Escherichia coli codA-coding sequence encoding CD, together with appropriate regulatory elements, was introduced into Arabidopsis. Neither untransformed controls, nor transgenic plants expressing no CD mRNA, were sensitive to 5FC. Conversely, for most transgenic plants expressing CD mRNA, in the presence of 5FC calli and seedlings failed to proliferate, and seeds failed to germinate. A few transgenic plants with many codA copies expressed less CD mRNA and remained insensitive to 5FC, which likely reflected epigenetic repeat-induced gene silencing. Thus 5FC, presumably through conversion by the enzyme to 5FU, can be used to select against plants that express CD.

Original languageEnglish (US)
Pages (from-to)793-799
Number of pages7
JournalPlant Molecular Biology
Issue number4
StatePublished - Nov 1993
Externally publishedYes


  • Arabidopsis
  • cytosine deaminase
  • negative selection

ASJC Scopus subject areas

  • Genetics
  • Agronomy and Crop Science
  • Plant Science


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