ARRA: Transcriptional Regulatory Networks Controlling Higher Plant Embryogenesis

The proposed experimental plan will investigate regulation of key embryo factors by MADSdomain proteins, as well as to probe the nature of the auto- and cross-regulation among the B3-domain embryo factors. The transcriptional regulatory network underpinning embryogenesis will be further investigated by determining the numbers and types of genes regulated by FUS3 using chromatin immunoprecipitation (ChiP) with tiling arrays to map, genome wide, FUS3 binding sites. Expression in response to loss- and gain-of-function of FUS3 will be determined in high-throughput manner using Affymetrix ATH1 arrays. These approaches will allow determination of the set of genes that are direct targets of FUS3 and those that are further downstream in the network. This type of work has already been accomplished in the PI's lab for global analysis of AGL 15 targets, and in future collaborations with other groups will lead to a global understanding of gene networks during embryogenesis. Even with the limited information available about targets of embryo transcription factors, it is apparent that there will be extensive cross-regulation as evidenced by multiple regulatory inputs controlling hormone accumulation and function. Experiments to investigate interactions between GA and other hormones/signaling pathways in embryogenesis are proposed.