Changing images of the gene.

During the twentieth century the gene emerged as the major driving force of biology. Initially, even the nature and behavior of gene vehicles, the chromosomes, were subjected to doubts. The basic or standard gene concept, as a unit of function, mutation, and recombination, had to be revised.

Rapid identification of Arabidopsis insertion mutants by non-radioactive detection of T-DNA tagged genes.

To assist in the analysis of plant gene functions we have generated a new Arabidopsis insertion mutant collection of 90 000 lines that carry the T-DNA of Agrobacterium gene fusion vector pPCV6NFHyg. Segregation analysis indicates that the average frequency of insertion sites is 1.29 per line, predicting about 116 100 independent tagged loci in the collection.

Distribution of 1000 sequenced T-DNA tags in the Arabidopsis genome.

Induction of knockout mutations by T-DNA insertion mutagenesis is widely used in studies of plant gene functions. To assess the efficiency of this genetic approach, we have sequenced PCR amplified junctions of 1000 T-DNA insertions and analysed their distribution in the Arabidopsis genome. Map positions of 973 tags could be determined unequivocally, indicating that the majority of T-DNA insertions landed in chromosomal domains of high gene density.

Pleiotropic control of glucose and hormone responses by PRL1, a nuclear WD protein, in Arabidopsis.

The prl1 mutation localized by T-DNA tagging on Arabidopsis chromosome 4-44 confers hypersensitivity to glucose and sucrose. The prl1 mutation results in transcriptional derepression of glucose responsive genes defining a novel suppressor function in glucose signaling. The prl1 mutation also augments the sensitivity of plants to growth hormones including cytokinin, ethylene, abscisic acid, and auxin; stimulates the accumulation of sugars and starch in leaves; and inhibits root elongation.