The AT-hook/PPC domain protein TEK negatively regulates floral repressors including MAF4 and MAF5

Epigenetic regulations of transposable elements (TEs) and TE-like repeat sequences help to protect genomic integrity and control various developmental processes, including flowering time. This complex action of gene silencing requires the coordination of many key players including DNA methylases, histone deacetylases and histone methyltranferases. We have recently reported that an AT-hook DNA binding protein, TRANSPOSABLE ELEMENT SILENCING VIA AT-HOOK (TEK), participates in silencing TEs and TE-like sequence containing genes, such as Ler FLOWERING LOCUS C (FLC) and FWA. TEK knockdown in amiTEK plants causes increased histone acetylation, reduced H3K9me2 and DNA hypomethylation in the target loci, which ultimately leads to the upregulation of FLC and FWA as well as TE reactivation. In this report, we show that, besides FLC, other FLC-like genes MADS AFFECTING FLOWERING 4 (MAF4) and MAF5 are also upregulated in amiTEK. Here we discuss the role of the nuclear matrix protein TEK in the maintenance of genome integrity and in the control of flowering.