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18th International Symposium on Iron Nutrition and Interaction in Plants
Madrid – May 30-June 3 2016
Interactions and functions of the transcription factor network for iron-regulated
responses
Daniela Lichtblau*, Birte Schwarz and Petra Bauer
Institute of Botany, Heinrich-Heine University, Universitätsstraße 1, D-40225 Düsseldorf, Germany
*[email protected]
Iron (Fe) is an essential micronutrient for plants as well as animals. Despite the fact that a great amount of iron
is present in the soil, most of it is insoluble and cannot simply be taken up by plants. Because of the strong
requirement for Fe on one hand and the Fe-toxicity on the other hand, a very sensitive fine-tuned mechanism
(up- and downregulation) of iron deficiency response genes is needed. To cope with changing environmental
conditions the iron uptake system and homeostasis is controlled by a complex network of different transcription
factors (TF) and other types of proteins [1].
In A. thaliana roots the FER-LIKE IRON DEFICIENCY-INDUCED TRANSCRIPTION FACTOR (FIT) plays a
major role for the regulation of iron uptake. As a heterodimer with one of the Ib subgroub bHLH´s transcription
factors it regulates the expression of several iron deficiency response genes such as AHA2, FERRIC
REDUCTION OXIDASE 2 (FRO2) and IRON-REGULATED TRANSPORTER 1 (IRT1) [2]. Besides FIT other
transcription factors take part in the iron deficiency response. Some are directly regulated by FIT, others can
be induced independently via the Fe status. FIT also interacts with transcription factors from other signaling
pathways (EIN3, ZAT12) whereby the influence of different signaling pathways can lead to the activation/
inactivation of iron deficiency response genes [3,4].
It might be possible that the known transcription factors which form hetero- and homodimers among each other
show a distinct hierachial cluster in order to regulate the expression of downstream iron response components.
This also raises the question whether there are more yet unknown factors involved in initiating and maintaining
the iron deficiency response. The aim of this work is to shed light on the hierarchy of transcription factors
through investigation of protein-protein interactions.
Keywords: iron homeostasis, transcriptional regulation, protein-protein interactions
References:
1) Ivanov R., Brumbarova T., Bauer P. (2012) Molecular Plant 5(1):27-42
2) Yuan Y., Wu H., Wang N., Li J., Zhao W., Du J., Wang D., Ling H. (2008) Cell Research 18: 385397
3) Lingam S., Mohrbacher J., Brumbarova T., Potuschak Th., Fink-Staube C., Blondet E., Genschik
P., Bauer P. (2011) The Plant Cell 23: 1815-1829
4) Le C., Brumbarova T., Stoof C., Weber E., Mohrbacher J., Frink-Staube C. Bauer P. (2016) Plant
Physiol. 170(1): 540-557
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