The mechanism and network of BES1 mediated transcriptional regulation in Brassinosteroids (BR) pathway in Arabidopsis

Abstract

<p>Brassinosteroids (BRs) are a family of steroid hormones present ubiquitously in plant</p> <p>kingdoms and play important roles throughout plant growth and development. BRs signal to</p> <p>regulate BES1 and BZR1 family transcription factors, which regulate target genes for various</p> <p>BR responses. However, our knowledge about the transcriptional network and mechanisms</p> <p>through which BES1 regulates gene expression is still limited. Background information about</p> <p>BR signaling and transcriptional regulation is presented in Chapter 1.</p> <p>The goal of my research is to understand the mechanism and network for BES1</p> <p>mediated transcription regulation using both forward and reverse genetics, as well as</p> <p>genomic approaches. Specifically, my thesis includes three main projects I have been</p> <p>worked on. Chapter 2 is about the transcription factor AtMYB30 that was identified as BR-</p> <p>induced transcription factor. I found that AtMYB30 is a BES1 direct target and meanwhile its</p> <p>protein helps BES1 to activate downstream target genes. Chapter 3 describes the discovery</p> <p>of a novel transcription elongation factor AtIWS1 required for BES1-regulated gene</p> <p>expression, which was identified by a forward genetics screen. In chapter 4, I describe a</p> <p>collaborative project in which we used chromatin immunoprecipitation coupled with tiling</p> <p>arrays (ChIP-chip), global gene profiling, as well as computational modeling to construct and</p> <p>validate a BR-transcriptional network. Finally, conclusions and future directions are</p> <p>summarized in chapter 5.</p>