Name: Andre Irsigler
Position: Postdoctoral Fellow
Contact: irsigler@bio.fsu.edu
Hometown: Juiz de Fora, MG - Brazil
Education: Ph.D. (2006); M.S. (2002); B.S. (2000). Universidade Federal de Vi├žosa, Brazil.

Gene regulation in higher organisms has been shown to be an intricate process, involving genetic and epigenetic factors. Transcription is modulated by proteins that bind promoter elements of genes, adapting gene expression to environmental conditions, presence of pathogens, stage of development and tissue type. Regulation of transcription is also influenced by the chromatin state and accessibility to regulatory proteins, involving mechanisms dependent on non-coding RNA, DNA methylation and histones modification. The relation between these factors affecting epigenetic gene regulation is still not very clear, and the components of the regulatory machinery are not fully identified.

We use maize as a system for studying epigenetic gene regulation. Maize has a large and complex genome, with well characterized genetics, and it is an important crop for humans and other animals.

A stable maize line with a silenced transgene has been used for screening of mutants defective in gene silencing. This transgene encodes b1, a transcription factor that activates anthocyanin production. Mutants defective in gene silencing develop a purple phenotype clearly detectable, resulted from the reactivation of this transgene. I am focusing on characterizing the mutant line Tgr2 (Transgene reactivated 2), using Nimblegen expression arrays and quantitative PCR to analyze gene expression.

Other approaches that we are currently using to study epigenetic regulation in maize include tethering chromatin remodelers close to a reporter transgene for understanding basis of chromatin modification; and characterization of complexes of silencing effectors.