Factors affecting nuclear dynamics and green fluorescent protein targeting to the nucleus in Arabidopsis thaliana roots

Nuclear movement and targeting of a green fluorescent protein (GFP)-nuclear localization sequence (NLS)-β-glucuronidase (GUS) chimeric protein to the roots of transformed Arabidopsis has been studied using time lapse analysis. To characterize the mechanism governing this movement, metabolic inhibitors, and chemicals that alter the concentrations of divalent cations in the cell were applied. Flow cytometry was used to examine the condition of nuclear membranes. The results showed that nuclear movement in Arabidopsis roots was energy-dependent. The concentration of magnesium ions seemed to play a crucial role in the movement of the nuclei and targeting of the chimeric GFP protein into the nucleoplasm. In contrast, alterations in concentration of calcium ions did not affect either nuclear dynamics or nucleoplasmic GFP accumulation. The results are discussed in terms of some of the physiological processes occurring within the cell.