The Fischer lab is interested in the epigenetic regulation of seed development in angiosperms, specifically Arabidopsis thaliana and Oryza sativa (rice).  Our main focus is investigation of the role of DNA methylation in the sexual reproduction of A. thaliana, specifically the process of DNA demethylation.  DNA demethylation is required for normal seed development, and is carried out in the male and female gametophytes by the DNA glycosylase DEMETER (DME;  the goddess of harvest).  In the female gametophyte, DME is expressed specifically in the central cell, and in the male gametophyte, it is expressed in the vegetative cell.  The lab uses a combination of molecular and genetic techniques to delineate the complex interactions between epigenetic regulators involved in seed development, and develops approaches to facilitate physical dissection of the intricate components of developing gametophytes.

Panel 1, A developing ovule in an A.thaliana ovary, stained with GUS to show DEMETER (DME) expression specifically in the central cell of the female gametophyte, from Choi et al., 2002.  Panel 2: The female gametophyte; CCN = central cell nucleus; ECN = egg cell nucleus; SP = sperm cell and PT = pollen tube.  Panels 3 and 4: The arabidopsis flower shows the growth of the pollen tube within the ovary.  Panel 5: The male gametophyte contains the vegetative nucleus and two sperm cells with in the vegetative cell.  DME is expressed in the vegetative nucleus, from Schoft et al., 2011.