Dissection of the Interactome and the Regulatory Network of the Dual-Function Transcription Factor Ying Yang 1, a Master Regulator of Plant Stress Responses and Development

Climate change and increasing exposure to environmental stress make adaptation and defence responses to one of the most significant factors for crop yield and quality.

At molecular level, stress-inducible master regulators and key transcription factors translate the stress-signalling into defence and developmental responses at the level of chromatin and gene expression. The dual function transcription factor YIN YANG 1 (YY1) is evolutionary conserved between animal and plant kingdom.

In Arabidopsis, the ABA-inducible YY1 is a negative regulator and key component of ABA responses, contributes to the plant resistance to fungal infection and UV-B radiation, and controls flowering time. Some stress related functions of YY1 are conserved between Arabidopsis and Populus tree.

Published and the preliminary data indicate that the stress-inducible YY1 in Arabidopsis is a hub that converts stress-signals into defence and developmental responses through interaction with transcription and epigenetic factors controlling common target genes. However, neither the protein-protein interactome nor the direct target genes of YY1 were intensively investigated.

On the level of protein-protein interactome of YY1, the comparison of published YY1-Flag IP-MS data with the preliminary Y2H screen data did not find any overlap, although both groups of YY1 interaction candidates contained transcription and epigenetic regulators.

These findings and theoretical considerations suggest that large parts of the 'dark interactome' of YY1 wait still to be discovered.

Regarding the direct target genes, the proposed ChIP-Seq approaches are the first attempt to study YY1-DNA binding at a global scale.

The anticipated results will have a deep impact on understanding of the complex protein-protein interactome of YY1, will identify the direct target genes of YY1, and will contribute to the development of applied approaches in crop plants that could benefit from optimised stress responses orchestrated by YY1.