Bromodomain proteins GTE9 and GTE11 are essential for specific BT2-mediated sugar and ABA responses in Arabidopsis thaliana
Global Transcription Factor Group E proteins GTE9 and GTE11 interact with BT2 to mediate ABA and sugar responses in Arabidopsis thaliana.
BT2 is a BTB-domain protein that regulates responses to various hormone, stress and metabolic conditions in Arabidopsis thaliana. Loss of BT2 results in plants that are hypersensitive to inhibition of germination by abscisic acid (ABA) and sugars. Conversely, overexpression of BT2 results in resistance to ABA and sugars. Here, we report the roles of BT2-interacting partners GTE9 and GTE11, bromodomain and extraterminal-domain proteins of Global Transcription Factor Group E, in BT2-mediated responses to sugars and hormones. Loss-of-function mutants, gte9-1 and gte11-1, mimicked the bt2-1-null mutant responses; germination of all three mutants was hypersensitive to inhibition by glucose and ABA. Loss of either GTE9 or GTE11 in a BT2 over-expressing line blocked resistance to sugars and ABA, indicating that both GTE9 and GTE11 were required for BT2 function. Co-immunoprecipitation of BT2 and GTE9 suggested that these proteins physically interact in vivo, and presumably function together to mediate responses to ABA and sugar signals.
KeywordsBromodomain proteins Global Transcription Factor Group E protein (GTE) Co-immunoprecipitation BTB domain protein Abscisic acid (ABA)
We thank Drs. Wayne Versaw (Texas A&M University), Sonia Irigoyen and Renesh Bedre (Texas A&M AgriLife Research) for valuable discussion and help during the study and preparation of this manuscript. The study was partly funded by National Science Foundation grant (MCB0244159) to T.D.M. and USDA National Institute of Food and Agriculture to K.K.M (HATCH TEX09621).
AM and KKM conceived and designed research. AM and KKM conducted experiments. AM and KKM analyzed data. AM, KKM and TDM wrote the manuscript. All authors read and approved the manuscript.
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