Identification of auxin-responsive elements of parB and their expression in apices of shoot and root.
Detailed analysis of transgenic tobaccos containing a series of chimeric parB promoter/beta-glucuronidase (GUS) gene constructs allowed us to define two auxin-responsive elements (AREs) of 48 bp and 95 bp (positions -210 to -163 and -374 to -280) in the parB promoter. The two AREs responded independently to physiological concentrations of auxin. Gel retardation assays revealed binding of nuclear protein(s) to the sequence conserved between ARE I and ARE II. The auxin responsiveness of the parB promoter did not mediate the pathway through the as-1 element and transcription factor ASF-1. AREs I and II were responsive to auxin at physiological concentrations, whereas as-1 responded only to higher concentrations of auxin which may be interpreted as stress, though as-1 had been reported to be a minimal ARE [Liu, X. & Lam, E. (1994) J. Biol. Chem. 269, 668-675]. Histochemical staining of transgenic tobacco that contained a parB promoter/GUS construct demonstrated the expression of GUS activity in the shoot apex as well as in the root tips, suggesting the involvement of parB expression in meristematic activity or differentiation. The drastic change in auxin responsiveness in the transgenic plants between the 6th and 10th day after imbibition of seeds implies the development or the activation of auxin signal transduction systems during plant development.
Takahashi
Y
Y
Department of Biological Sciences, Graduate School of Science, University of Tokyo, Japan.
Sakai
T
T
Ishida
S
S
Nagata
T
T
D001426:Bacterial Proteins / Q000096:biosynthesis* / Q000235:genetics; D001483:Base Sequence; D001665:Binding Sites; D017124:Conserved Sequence; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant; D005966:Glucuronidase / Q000096:biosynthesis; D007210:Indoleacetic Acids / Q000378:metabolism*; D008969:Molecular Sequence Data; D009687:Nuclear Proteins / Q000378:metabolism*; D015345:Oligonucleotide Probes; D018517:Plant Roots; D030821:Plants, Genetically Modified; D010947:Plants, Toxic; D010957:Plasmids; D011401:Promoter Regions, Genetic; D011993:Recombinant Fusion Proteins / Q000096:biosynthesis; D015183:Restriction Mapping; D014026:Nicotiana / Q000254:growth & development / Q000378:metabolism*; D014157:Transcription Factors / Q000378:metabolism
D001426:Bacterial Proteins; D007210:Indoleacetic Acids; D009687:Nuclear Proteins; D015345:Oligonucleotide Probes; D011993:Recombinant Fusion Proteins; D014157:Transcription Factors; C052883:chromosome partition proteins, bacterial; D005966:Glucuronidase