Wheat RAN1 affects microtubules integrity and nucleocytoplasmic transport in fission yeast system

Ran is an evolutionarily conserved eukaryotic GTPase that directly participates in cell cycle and whose loss affects many biological processes. We have identified cDNA of TaRAN1, a novel Ran GTPase homologous gene in wheat (Triticum aestivum L. cv. Jingdong No. 1). The cytoplasmic microtubules play an important role in cytoplasmic organization, cell division, and the correct transmission of genetic information in fission yeast cell. Using the fission yeast system in vivo experiments, overexpression of TaRAN1 produced defective spindle microtubules, probably resulting in chromosome missegregation we reported previously. The microtubules of antisense TaRAN1 yeast cells were physically disrupted. This suggested that TaRAN1 plays a role in mitotic spindle assembly and microtubule integrity and stability. Ultrastructural analysis under transmission electron microscope (TEM) showed abnormal nuclear membranes in the overexpression TaRAN1 yeast cells, abnormal vacuole structures and disorganized membranes in the antisense TaRAN1 yeast cells. These results suggested that TaRAN1 was essential for all nucleocytoplasmic transport events.