Arabidopsis Molecular Genetics
Arabidopsis, methylation, silencing, siRNA, epigenetics
Arabidopsis is an inconspicuous weed and it is also the most intensively studied plant in the world. The Furner lab has been involved in Arabidopsis research for 25 years. Much of the effort has been in the area of gene silencing and particularly in the field of homology-dependant gene silencing (HDG silencing). Briefly, regions of the genome can influence the expression and chromatin state of homologous regions in the genome by an epigenetic mechanism involving RNA directed DNA methylation. The normal biological role of this mechanism is to down-regulate expression of genes and transposons both in large blocks at the centromeres and scattered throughout the genome.
When transgenes are introduced into the genome they can interact with the HDG silencing mechanism resulting in transgene silencing and/or the silencing of homologous genes at distant sites. We have been studying this phenomenon using the Arabidopsis genes CHALCONE SYNTHASE (CHS) and CHLORATA 42 (CH-42). CHS is required for biosynthesis of the purple pigment anthocyanin and CH-42 is required for the synthesis of the green pigment chlorophyll. Plants showing silencing of these genes are deficient in the corresponding pigments. For example, plants showing CH-42 silencing are yellow or variegated (striped). The Furner lab has been using forward and reverse genetics, transgenesis, genomics, transcript profiling and bisulphite sequencing to gain insight in to the genes and molecular mechanisms involved in HDG silencing between extra copies of these genes and the homologous endogenous loci.
4 key publications
- Furner I.J. and Matzke M. (2011) Methylation and demethylation of the Arabidopsis genome. Current Opinion in Plant Biology 14: 137-141
- Daxinger L., Hunter B., Sheikh M., Jauvion V., Gasciolli V., Vaucheret H., Matzke M. and Furner I.J. (2008) Unexpected silencing effects from T-DNA tags in Arabidopsis. Trends in Plant Sciences 13: 4-6
- Jordan N.P., West J., Bottley A., Sheikh M. and Furner I.J. (2007) Transcript profiling of the hypomethylated hog1 mutant of Arabidopsis. Plant Molecular Biology. 65: 571-586
- Rocha. P.S.C.F., Sheikh, M., Melchiorre, R., Fagard, M., Boutet, S., Loach, R., Moffatt, B., Wagner, C., Vaucheret, H., and Furner, I.J. (2005). The Arabidopsis HOMOLOGY-DEPENDENT GENE SILENCING1 gene codes for a S-adenosyl-L-homosysteine hydrolase required for DNA methylation dependent gene silencing. The Plant Cell 17: 404-417