Doris Wagner
Associate Professor, Dept of Biology

Genetics and Gene Regulation Program

Developmental Biology Program

Address

103G Lynch Building

Office tel.: 215 898-0483
Lab tel.: 215 898-0484
Fax: 215 898-8780
E-mail: wagnerdo@sas.upenn.edu

Link(s)

Dr Wagner at the Dept of Biology

EDUCATION

Universität München, Weihenstephan, Vordiplom (Plant Biology) 1988

University of California at Berkeley, PhD (Photoreceptor signal transduction; structure/function studies of the photoreceptor) 1995

California Institute of Technology, , postdoctoral research (Molecular/Genetic Investigation of the Developmental Transition to Reproductive Development) 2000

Research Interests

• Molecular mechanisms controlling developmental transitions and transcriptional reprogramming in response to environmental and endogenous cues.

Key words: Chromatin remodeling, Transcriptional regulation, Development.

Search PubMed for articles

Description of Research

Research Interests
My lab is interested in understanding how genomes compacted into chromatin are made accessible during development or in response to environmental signals. We study one of the two known mechanisms that control 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 mechanism that controls the vital transition to reproductive development in the plant model system Arabidopsis thaliana. Specifically, we investigate the signaling events between one key regulator necessary and sufficient for this transition, the LEAFY (LFY) protein and the floral homeotic genes that specify reproductive organ formation.

Role of chromatin remodeling in development
My lab studies the role of chromatin remodeling in multicellular eukaryote growth and development. We focus on the SWI/SNF chromatin remodeling ATPases known to be important for transcriptional regulation in the context of chromatin. We have identified viable null alleles for two SWI/SNF chromatin remodeling ATPases in Arabidopsis thaliana that have strong pleiotropic phenotyes. This is a unique system for investigating the in vivo role of these regulators as most metazoan SWI/SNF ATPases are embryonic lethal. 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. We are currently identifying the direct targets of the chromatin remodeling ATPases and investigating how they are recruited to these targets

Signaling events downstream of LEAFY
LEAFY (LFY) is a plant specific transcription factor and master regulator that controls the onset of reproduction. A chimeric version of LFY and the rat glucocorticoid receptor hormone binding domain (LFY-GR) can be post-transtionally activated. This allowed us to identify new direct targets of LFY using global expression studies in the presence of a protein synthesis inhibitor. Chromatin immuno-precititation (ChIP) confirmed binding of LFY to the target promoters. Using genetic and reverse genetic approaches, we demonstrated that the five most highly induced direct LFY targets indeed act downstream of LFY in the pathway that controls reproductive development. We are now using global binding studies (ChIP-on-chip) to further dissect the role of LFY in this vital developmental transition.

Recent Publications

Chromatin Remodeling

Kwon, C.S., and Wagner, D. (2007). Unwinding chromatin for development and growth: a few genes at a time. Trends Genet.

Bezhani, S., Winter, C., Hershman, S., Wagner, J.D., Kennedy, J.F., Kwon, C.S., Pfluger, J., Su, Y., and Wagner, D. (2007). Unique, shared and redundant roles for the Arabidopsis SWI/SNF chromatin remodeling ATPases BRAHMA and SPLAYED. Plant Cell 19, 403-416, featured article.

Kwon, C.S., Chen, C., and Wagner, D. (2005). WUSCHEL is a primary target for transcriptional regulation by SPLAYED in dynamic control of stem cell fate in Arabidopsis. Genes Dev 19, 992-1003.

LEAFY transcription factor

Saddic, L., Huvermann, B., Bezhani, S. Yanhui, S., Winter, C., Kwon, C.S., Collum, R., and Wagner, D. (2006). The LEAFY target LMI1 is a meristem identity regulator and acts together with LEAFY to regulate expression of CAULIFLOWER. Development 133,1673-1682, featured article

William, D.A., Su, Y., Smith, M.R., Lu, M., Baldwin, D.A., and Wagner, D. (2004). Genomic identification of direct target genes of LEAFY. Proc Natl Acad Sci U S A 101,1775-1780.

Lab

Rotation Projects

Please contact Doris Wagner

Lab personnel:

Dr. Staver Bezhani, postdoc
Dr. Jennifer Pfluger, postdoc
Dr. Yi Sang, postdoc
Dr. Ayako Yamaguchi, postdoc
Jennifer Pastore, graduate student
Cara Winter, graduate student
Soon-Ki Han, student researcher
Zhenteng Li, undergraduate
Lauren Malaspina, undergraduate
Yanhui Su, lab manager