Lamin-like analogues in plants: the characterization of AcNMCP1

Abstract

The nucleoskeleton of plants contains a peripheral lamina also called plamina, and even though lamins are absent in plants, their roles are still fulfilled in plant nuclei. One of the most intriguing topics in plant biology concerns the identity of lamin protein analogues in plants. Good candidates to play lamin functions in plants are the members of the NMCP (nuclear matrix constituent protein) family, which exhibit the typical tripartite structure of lamins. Here, we describe a bioinformatics analysis and the classification of the NMCP family based on phylogenetic relationships, sequence similarity and the distribution of conserved regions in 76 homologues. In addition, we characterized NMCP1 in the monocot Allium cepa, determining its sequence and structure, biochemical properties and sub-nuclear distribution, and identifying alterations in its expression throughout the root. Our results demonstrate that these proteins exhibit many similarities to lamins (structural organization, conserved regions, subnuclear distribution and solubility) and that they may fulfil the functions of lamins in plants. These findings significantly advance our understanding of the structural proteins of the plant lamina and nucleoskeleton, and they provide a basis for further investigation of the protein networks forming these structures.