The WD40-repeat proteins nfc101 and nfc102 regulate different aspects of maize development through chromatin modification mechanisms

The maize (Zea mays) nucleosome remodeling factor complex component 101 and 102\r\n(nfc101/nfc102) are putative paralogs encoding WD-repeat proteins that exhibit homology with\r\nplant and mammalian components of various chromatin modifying complexes. In this study, we\r\ngenerated transgenic lines with simultaneous nfc101 and nfc102 down-regulation and analyzed\r\nphenotypic alterations, along with effects on RNA levels, the binding of nfc101/nfc102 and Rpd3-\r\ntype histone deacetylases (HDACs), and histone modifications at selected targets. Direct\r\nnfc101/nfc102 binding and negative correlation with mRNA levels were reported for key activators\r\nof the floral transition, such as indeterminate 1 (id1) and the florigen ZCN8. In addition, the\r\nabolition of nfc101/nfc102 association with repetitive sequences of different transposable elements\r\n(TEs) resulted in tissue-specific up-regulation of transcripts produced by these regions. All direct\r\nnfc101/nfc102 targets showed histone modification patterns linked to active chromatin in\r\nnfc101/nfc102 down-regulation lines. However, different mechanisms may be involved because\r\nnfc101/nfc102 proteins mediate HDACs recruitment at id1 and TE repeats, but not at ZCN8. These\r\nresults, along with the pleiotropic effects observed in nfc101/nfc102 down-regulation lines, suggest\r\nthat nfc101 and nfc102 are components of distinct chromatin modifying complexes, which operate\r\nin different pathways and influence diverse aspects of maize development