Analysis of the interaction between Arabidopsis ERF13, WRKY33 and the TGMV AL1629 promoter

Date
2012
Authors
Samant, Neha Shirish
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Abstract

Tomato Golden Mosaic virus (TGMV), a member of the Geminiviridae family of plant-infecting DNA viruses, is able to interact with different host factors to regulate its gene expression. The TGMV AL2 protein is a transcriptional activator, encoded by the AL1629 complementary sense transcript. My research focuses on the TGMV AL1629 promoter and its interaction with Arabidopsis transcription factors. It has been previously reported that a host factor, Ethylene Response Factor 13 (AtERF13) binds to a specific nine base pair sequence (AACGTCATC) within the TGMV AL1629 promoter. My results demonstrate that AtERF13 interacts with the TGMV AL1629 promoter in vivo using Chromatin Immunoprecipitation (ChIP). ERFs are transcription factors that are induced upon external stimuli including viral challenge, and I have shown ERF13 is induced upon TGMV infection within 24 hours, after which expression levels decrease as over time. This suggests that induction of ERF by geminivirus infection is an early response. Although ERFs appear to bind to GCC box sequences within promoters, the TGMV AL1629 promoter lacks such a sequence element. However, Tomato ERF Pti4 interacts with both GCC as well as non-GCC containing promoter sequences. This suggests the possibility that ERFs may interact with promoters in conjunction with other host factors. My studies have revealed an interaction between AtERF13 and AtWRKY33, another plant transcription factor that plays a role in the positive regulation of transcription. This work suggests that a complex consisting of AtERF13 and AtWRKY33 may regulate the geminivirus AL1629 promoter to activate AL2 gene expression. Together these results indicate that geminiviruses may target proteins induced in response to infection for regulation of viral genes. Disrupting interactions between virus and host could provide a way to develop resistance strategies against this devastating group of plant viruses.

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Keywords
AL1629, Promoter, ERF13, WRKY 33, Tomato Golden Mosaic Virus
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Department
Integrative Biology