Doris Wagner, PhD

Description of Research Expertise

Research Interests
Molecular mechanisms controlling developmental transitions in response to environmental and endogenous cues.

Key words: Transcriptional Regulation, Development, Chromatin Remodeling

Description of Research
My lab is interested in understanding how the accessibility of genomes compacted into chromatin is altered in response to developmental or environmental signals. We study one of the two known mechanisms that can alter access to the genetic information in the context of chromatin, ATP-dependent chromatin remodeling. A second focus of the lab is elucidation of the molecular mechanisms that underlie the vital transition to reproductive development in the plant model system Arabidopsis thaliana. Specifically, we investigate how the master transcription regulator LEAFY (LFY) direct primordium formation and program the primordium founder cells to adopt a floral fate during the onset of reproduction.

Role of chromatin remodeling in development
My lab studies the role of chromatin remodeling in multicellular eukaryote growth, response to stress and development. We use Arabidopsis thaliana as a model system. Plants are an ideal system for studying chromatin mechanisms, as sessile organisms they have evolved adaptive mechanisms for altering cell function and even their body plan in response to different environments. In addition, in contrast to metazoan SWI/SNF ATPases, single null mutations in plant SWI/SNF ATPases cause severe development and growth aberrations, but are not embryonic lethal; facilitating their genetic investigation. Our combined genetic, molecular and genomic studies have revealed that these chromatin remodeling ATPases regulate many distinct processes. In each process they control expression of one or very few key regulators. This surprising functional specificity is in contrast to their previous classification as ‘general’ transcriptional co-regulators. Our current research aims to elucidate how this specificity is achieved.

Developmental reprogramming by the LEAFY transcription factor
LEAFY (LFY) is a helix-turn-helix transcription factor and master regulator that controls the onset of reproduction. Using both global expression and binding studies, we have identified the direct LFY targets at two developmental stages. LFY has stage-specific roles that are in part mediated by interactions with chromatin regulators. We are now studying the roles of the LFY targets in the transition to reproductive development.

Techniques employed
Molecular biology; (Epi)Genomics; Developmental biology; Genetics; Biochemistry

Rotation Projects for 2009-2010
1. Genetic and genomic investigation of the role of chromatin remodeling in pluripotency and differentiation
2. Recruitment of chromatin complexes to target genes
3. Function of LEAFY targets in the reproductive transition
4. Induction of LEAFY mRNA expression and regulation of LFY activity
5. Organogenesis in plants


Lab personnel:
Dr. Kostas Vlachonasios; sabbatical visitor
Dr. Miin-Feng Wu; postdoc
Dr. Nobutoshi Yamaguchi; postdoc
Soon-Ki Han; graduate student
Gleb Bazilevsky; rotation student