Plant Molecular Biology

, Volume 21, Issue 5, pp 895–906

The intron of Arabidopsis thaliana polyubiquitin genes is conserved in location and is a quantitative determinant of chimeric gene expression

  • Susan R. Norris
  • Sandra E. Meyer
  • Judy Callis
Research Articles

DOI: 10.1007/BF00027120

Cite this article as:
Norris, S.R., Meyer, S.E. & Callis, J. Plant Mol Biol (1993) 21: 895. doi:10.1007/BF00027120

Abstract

We have isolated and determined DNA sequence for the 5′-flanking regions of three Arabidopsis thaliana polyubiquitin genes, UBQ3, UBQ10, and UBQ11. Comparison to cDNA sequences revealed the presence of an intron in the 5′-untranslated region at the same position immediately upstream of the initiator methionine codon in each of the three genes. An intron at this position is also present in two sunflower and two maize polyubiquitin genes. An intron is also found in the 5′-untranslated regions of several animal polyubiquitin genes, although the exact intron position is not conserved among them, and none are in the same position as those in the higher plant polyubiquitin genes. Chimeric genes containing the 5′-flanking regions of UBQ3, UBQ10, and UBQ11 in front of the coding regions for the reporter enzyme Escherichia coli β-glucuronidase (GUS) were constructed. When introduced transiently into Arabidopsis leaves via microprojectile bombardment, all resulted in readily detectable levels of GUS activity that were quantitatively similar. The introns of UBQ3 and UBQ10 in the corresponding promoter fragments were removed by replacement with flanking cDNA sequences and chimeric genes constructed. These constructs resulted in 2.5- to 3-fold lower levels of marker enzyme activity after transient introduction into Arabidopsis leaves. The UBQ10 promoter without the 5′ intron placed upstream of firefly luciferase (LUX) resulted in an average of 3-fold lower LUX activity than from an equivalent construct with the UBQ10 intron. A UBQ3 promoter cassette was constructed for the constitutive expression of open reading frames in dicot plants and it produced readily detectable levels of GUS activity in transient assays.

Key words

polyubiquitin Arabidopsis thaliana introns chimeric genes constitutive promoter transient assays 

Copyright information

© Kluwer Academic Publishers 1993

Authors and Affiliations

  • Susan R. Norris
    • 1
  • Sandra E. Meyer
    • 1
  • Judy Callis
    • 1
  1. 1.Section of Biochemistry and BiophysicsUniversity of California-DavisDavisUSA
  2. 2.Department of Biochemistry, Biological Sciences West BuildingUniversity of ArizonaTucsonUSA

Personalised recommendations