Plant nuclear factor ASF-1 binds to an essential region of nopaline synthase promoter

E. Lam, F. Katagiri, N. H. Chua

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We have characterized a tobacco nuclear factor that binds to the -118 region of the nopaline synthase (nos) promoter from the Ti plasmid of Agrobacterium tumefaciens. The binding site for this factor, identified by DNase I footprinting, encompasses the region from -138 to -103 of the nos promoter. This region, which contains a potential Z-DNA-forming sequence, was previously shown to be essential for nos promoter activity in transgenic tobacco. A synthetic 21-base pair sequence from the protected region (from -131 to -111), designated as nos-1, was sufficient for factor recognition in vitro. In transgenic tobacco, a tetramer of nos-1 can confer leaf and root expression when fused upstream of a truncated 35 S promoter from the cauliflower mosaic virus. Mutations at the two TGACG-like motifs in nos-1 abolish factor binding while preserving the potential for Z-DNA formation. A tetramer of the nos-1 mutant sequence has no significant activity above background when tested in transgenic tobacco. Competition experiments with activation sequence factor (ADF)-1 binding sites from the 35 S promoter of cauliflower mosaic virus (as-1) and the wheat histone H3 promoter (hex-1) demonstrate that ASF-1 is the factor that binds to nos-1.

Original languageEnglish (US)
Pages (from-to)9909-9913
Number of pages5
JournalJournal of Biological Chemistry
Issue number17
StatePublished - 1990
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Biochemistry
  • Molecular Biology
  • Cell Biology


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