Identification and characterization of genes encoding the nuclear envelope LINC complex in the monocot species Zea mays

ABSTRACT The LINC (Linker of Nucleoskeleton to Cytoskeleton) complex is an essential multi-protein structure spanning the nuclear envelope. It connects the cytoplasm to the nucleoplasm, functions to maintain nuclear shape and architecture, and regulates chromosome dynamics during cell division. Knowledge of LINC complex composition and function in the plant kingdom is primarily limited to Arabidopsis, but critically missing from the evolutionarily distant monocots which include grasses, the most important agronomic crops worldwide. To fill this knowledge gap, we identified and characterized 22 maize genes, including a new grass-specific KASH gene family. Using bioinformatic, biochemical, and cell biological approaches, we provide evidence that representative KASH candidates localize to the nuclear periphery and interact with ZmSUN2 in vivo. FRAP experiments using domain-deletion constructs verified that this SUN-KASH interaction was dependent on the SUN but not the coiled-coil domain of ZmSUN2. A summary working model is proposed for the entire maize LINC complex encoded by conserved and divergent gene families. These findings expand our knowledge of the plant nuclear envelope in a model grass species, with implications for both basic and applied cellular research. SUMMARY STATEMENTGenes encoding maize candidates for the core LINC and associated complex proteins have been comprehensively identified with functional validation by one or more assays for several of the KASH genes.