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Wittgenstein Award Laureate 1997 Marjori + Antonius Matzke

Epigenetic silencing of plant transgenes, Austrian Academy of Sciences, ÖAW

WITNESSES OF DRASTIC EVENTS

The Austro-American research pair Antonius and Marjori Matzke is on the track of the molecular mechanisms that lead to gene inactivation and to the inheritance of transgenes in plants. It is hard to overestimate the theoretical importance of their work, which requires painstaking laboratory work on an extremely small scale.

The Matzkes discovered ”gene silencing” of homologous DNA sequences (sequences with identical information content) in transgenic plants. These sequences can interact in a way that leads to the inactivation of parts of the genome. Analyses during the last several years by the Matzke group has demonstrated that ”homology-dependent” gene inactivation can be ascribed to the action of double stranded RNA, which can somehow trigger silencing and modification at the DNA level. This area of research, recently renamed‚ ”RNA silencing” has grown dramatically as similar silencing phenomena, most notably RNA-interference (RNAi) has been discovered in animals. The evolutionary conservation of these silencing mechanisms points toward crucial roles in the development of plants, animals and fungi.

Marjori from Indiana and Antonius from Upper Austria met at the start of the 1980s while they were post-docs studying plant molecular biology at Washington University in St Louis. In 1983 the leading specialized journal Cell published the report of the first genetically produced plants and Antonius Matzke was one of the co-authors. From the following year onwards the Matzkes have jointly published all their research findings. As Marjori says, Austria offers them ideal conditions for working and a good international network. ”We are participating with eight other labs in an EU project on gene silencing and we often attend conferences. Nowadays you can no longer rely on people reading your papers. Part of scientific work is thus PR with other scientists.”

They want to carry out basic research and are glad to be supported in this. If research on gene silencing has practical applications, so much the better. As an example, the Malaysian palm oil industry is interested in blocking the undesired gene silencing that occurs unpredictably in cloned oil palms. The Matzke’s work has demonstrated that this silencing results from a failure to ”reset” the genome, which normally occurs during sexual reproduction, in cloned plants. Unwanted silencing of genes in cloned plants probably reflects a similar problem currently encountered in attempts to clone mammals, where high rates of mortality and developmental abnormalities are being attributed to misregulation of gene expression.

The 1997 Wittgenstein Prize ”has been fantastic for us.” The Matzkes can work towards long - term goals and start a few more risky projects. ”In our Arabidopsis programme we are carrying out a large-scale mutagenesis of the gene silencing system and we have already discovered several ‘putants’ [putative mutants].” A further discovery has been virus sequences integrated into tobacco chromosomes, the first example of such sequences in plants. This finding is suggesting new ways of genetically engineering virus resistance in plants and it might help to understand viral immunity in humans.

Marjori + Antonius Matzke