University of Pennsylvania School of Arts and Sciences
Department of Biology
103G Carolyn Lynch Laboratory
Philadelphia, PA 19104
Office: 215-898-0483
wagnerdo@sas.upenn.edu
Our research focuses on the reprogramming of cell identity and function during developmental transitions and in response to environmental inputs in plants. These sessile organisms are an excellent experimental system to address this question as they tailor their final form and cell function to a changing environment to optimize growth and survival. We have shown that master transcriptional regulators, hormone response and chromatin state together orchestrate cell fate reprogramming in plants.
The role and Regulation of SWI/SNF chromatin remodeling complexes in plants.
ATP-dependent chromatin remodeling can change the chromatin state by using the energy derived from ATP hydrolysis to alter histone/DNA interactions. We uncovered key roles for plant SWI/SNF subfamily remodelers in stem cell maintenance and in overcoming Polycomb repression for induction of the floral homeotic genes during flower patterning. Finally, activity of one of the SWI/SNF remodelers, BRM, is modulated directly by signaling components of the stress hormone ABA for drought tolerance.
The switch to flower formation, a major developmental switch critical for reproductive success.
Plants generate different types of lateral organs (leaves, then branches and finally flowers) post-embryonically from stem cell descendants at the shoot apex. When flowers form is critical for plant reproductive success. Our research has established that the plant specific helix-turn-helix transcription factor LEAFY is a key regulator of the onset of flower formation. We showed that the regulatory network downstream of LFY is comprised of a set of interlocking feed-forward loops that together control the timing of the upregulation of the direct LFY target APETALA1, a commitment factor of floral fate. We further found that LFY also directly alters the hormone environment in newly formed primordia to promote floral fate.
Organogenesis and differentiation in response to hormonal cues
We have recently become interested in the question how hormone responses control organogenesis and differentiation. We have identified key targets of the mater transcriptional regulator of the auxin hormone response, AUXIN RESPONSE FACTO5/MONOPTEROS during organogenesis (flower primordium initiation) and uncovered an auxin hormone triggered chromatin state switch. In addition, we have elucidated how BRM together with leaf maturation transcription factors triggers leaf differentiation by lowering response to the hormone cytokinin.
Polycomb silencing and recruitment in plants
Cell identity depends on silencing of unnecessary or detrimental gene expression programs. To understand the regulation of epigenetic gene silencing we have elucidated how Polycomb Repressive Complexes are targeted to developmental genes in plants. We have uncovered a genome-encoded recruitment mechanism very similar to that previously described in the fruitfly. Our studies pave the way to future epigenetic manipulation of desirable plant traits.
FIRST NAME: | LAST NAME: | TITLE: | EMAIL: |
---|---|---|---|
Doris | Wagner | PI | wagnerdo@sas.upenn.edu |
Min | Wang | postdoc | minniu@sas.upenn.edu |
Yang | Zhu | postdoc | yaz@sas.upenn.edu |
Sammy | Klasfeld | Graduate Student | sjk314@gmail.com |
Un-sa | Lee | Grad Student | unlee@sas.upenn.edu |
Run | Jin | Graduate Student | runjin@sas.upenn.edu |