For information on PhD studies at TLL, click HERE

• Transcriptional network of homeotic genes
• Gametophyte induction
• Mechanism for orchestrated transcriptional regulation

Research Projects

It is a longstanding mystery and very intriguing question how homeotic proteins specify the identity of different organs during morphogenesis in the study of not only plant but also animal development. The Arabidopsis homeotic gene AGAMOUS (AG), a MADS-box transcription factor, is necessary for the specification of reproductive organs. We aim to elucidate the transcriptional network from AG to downstream genes through the high-throughput analyses by microarray and chromatin immunoprecipitation. We will focus on the following four facets of the reproductive organ development:

1. Gametophyte induction - We have recently shown that AG regulates SPOROCYTELESS/NOZZLE (SPL) as a central mediator for microsporogenesis function. One project is to reveal downstream cascades of SPL controlling the transition from the sporophytic to the gametophytic phase.

2. Late stage function - In addition to playing a role in microsporogenesis, AG appears to have several different functions throughout the flower development. The second project is to reveal the function of continued expression of AG during the late stages of flower development.

3. Meristem determinacy - The third project involves another important function of AG: terminating meristematic activity in floral buds. Two other transcription factors, SUPERMAN (SUP) and WUSCHEL (WUS, downstream mediator for indeterminacy), also appear to function in this process. We are to fill a gap in the transcriptional cascades from AG to WUS, and also elucidate how SUP controls meristem determinacy.

4. Functional analysis of a nuclear protein - The fourth project is the functional characterization of one of our putative AG targets. This gene encodes a nuclear protein that may function by interacting with the nuclear matrix and recruiting chromatin remodeling enzymes. This project potentially reveals a mechanism for orchestrated transcriptional regulation of multiple genes during reproductive organ development.

Following the identification of biological key components during reproductive organ development, we will integrate all the information obtained from the high-throughput analyses and assemble it into a larger network structure. The “map” of network structure will reveal the dynamic and global gene expression programs that regulate the reproductive organ development.