A dominant negative mutant of PG13 suppresses transcription from a cauliflower mosaic virus 35S truncated promoter in transgenic tobacco plants.
TGA1a and PG13 constitute a family of tobacco basic leucine zipper (bZIP) proteins that bind to activating sequence-1 (as-1), which is one of the multiple regulatory cis elements of the cauliflower mosaic virus (CaMV) 35S promoter. After truncation of the CaMV 35S promoter down to position -90 (CaMV 35S [-90] promoter), transcription stringently depends on the presence of as-1, which is recognized by nuclear DNA binding proteins called ASF-1. The role of the TGA1a/PG13 bZIP family in the formation of ASF-1 and in transcriptional activation of the CaMV 35S (-90) promoter has not yet been demonstrated in vivo. We constructed transgenic tobacco plants expressing a mutant of potato PG13, which lacks its wild-type DNA binding domain. This mutant acts as a trans-dominant inhibitor of ASF-1 formation and of expression from the CaMV 35S (-90) promoter, showing that PG13 can specifically interact with proteins necessary for these processes. Although we did not observe any other obvious phenotypic changes, these transgenic plants are a potentially valuable tool in identifying whether TGA1a and PG13 are involved in controlling promoters encoded in the plant genome.
Rieping
M
M
Universität Bielefeld, Lehrstuhl für Genetik, Fakultät für Biologie, Germany.
Fritz
M
M
Prat
S
S
Gatz
C
C
D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D001483:Base Sequence; D050976:Basic-Leucine Zipper Transcription Factors; D017796:Caulimovirus / Q000235:genetics; D004268:DNA-Binding Proteins / Q000235:genetics* / Q000378:metabolism; D018506:Gene Expression Regulation, Plant; D016350:Leucine Zippers; D008969:Molecular Sequence Data; D009154:Mutation; D009687:Nuclear Proteins / Q000378:metabolism; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D018517:Plant Roots; D018520:Plant Shoots; D030821:Plants, Genetically Modified; D010947:Plants, Toxic; D011401:Promoter Regions, Genetic / Q000235:genetics; D011485:Protein Binding; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D012697:Serine Endopeptidases; D011198:Solanum tuberosum / Q000235:genetics*; D014018:Tissue Distribution; D014026:Nicotiana / Q000235:genetics; D014158:Transcription, Genetic; D000099160:LexA Repressor Protein
D001426:Bacterial Proteins; D050976:Basic-Leucine Zipper Transcription Factors; D004268:DNA-Binding Proteins; D009687:Nuclear Proteins; D010940:Plant Proteins; D011993:Recombinant Fusion Proteins; D012697:Serine Endopeptidases; D000099160:LexA Repressor Protein; C089914:PG13 protein, Nicotiana tabacum; C065794:TGA1a protein, Nicotiana tabacum