The emerging functions of mini zinc finger (MIF) microproteins in seed plants: A minireview.

Mini zinc fingers constitute a class of microproteins that appeared early in evolution and expanded in seeds plants. In this review, the phylogenetic history, the functions and the mode of action of MIFs in plants are reported and discussed. It appears that mini zinc finger microproteins play an important role in the control of plant development. They are involved in the control of cell division and expansion and in the switch between the determinate/indeterminate state of the meristems. They are involved in the regulation of vegetative growth and floral organ development. Their biochemical mode of action seems to be diverse. In some studies, it has been reported that mini zinc finger microproteins can directly bind to DNA and activate target gene expression, whereas other studies have shown that they can interact with and inhibit the activity of specific zinc finger homeodomain transcription factors or act as adaptor proteins necessary to aggregate polymeric protein complexes corresponding to chromatin remodelling factors negatively regulating the expression of specific genes. The diversity of mode of action for mini zinc finger microproteins suggests a wider range of biological functions than what has been that described in the literature thus far, and their involvement in the response to biotic and abiotic stresses should be further investigated in future studies.