The effect of magnesium on mitotic spindle formation in Schizosaccharomyces pombe

Abstract

Magnesium (Mg2+), an essential ion for cells and biological systems, is involved in a variety of cellular processes, including the formation and breakdown of microtubules. The results of a previous investigation suggested that as cells grow the intracellular Mg2+ concentration falls, thereby stimulating formation of the mitotic spindle. In the present work, we used a Mg2+-deficient Schizosaccharomyces pombe strain GA2, in which two essential membrane Mg2+ transporter genes (homologs of ALR1 and ALR2 in Saccharomyces cerevisae) were deleted, and its parental strain Sp292, to examine the extent to which low Mg2+ concentrations can affect mitotic spindle formation. The two S. pombe strains were transformed with a plasmid carrying a GFP-α2-tubulin construct to fluorescently label microtubules. Using the free Mg2+-specific fluorescent probe mag-fura-2, we confirmed that intracellular free Mg2+ levels were lower in GA2 than in the parental strain. Defects in interphase microtubule organization, a lower percentage of mitotic spindle formation and a reduced mitotic index were also observed in the GA2 strain. Although there was interphase microtubule polymerization, the lower level of mitotic spindle formation in the Mg2+-deficient strain suggested a greater requirement for Mg2+ in this phenomenon than previously thought.

Magnesium Is a Key Player in Neuronal Maturation and Neuropathology

“…The condensation of chromosomes by Mg 2+ is required for cell mitosis [40,53]. In yeast, the deficit of Mg 2+ intake interferes with the interphase microtubule organization and mitotic spindle formation [54]. In addition, some tumor cells contain higher levels of Mg 2+ in the nucleus compared with normal cells [50,55,56].…”

Vicia–Micronucleus Test Application for Saline Irrigation Water Risk Assessment

“…It is also a signal of mitosis sensitivity to the ion level in the medium which may, once in the cytosol, interfere with the cell cycle regulatory processes. Among cations that display interference with cell division, Mg 2+ is involved in the formation of mitotic spindle through polymerization and de-polymerization of microtubules (e.g., [ 31 ]). Abraham and Nair studied cytological changes produced in root meristems of V. faba after exposure to magnesium sulfate (MgSO 4 ) [ 32 ].…”

Magnesium depletion extends fission yeast lifespan via general amino acid control activation

“…The cellular responses identified here are summarized in Figure 6. Mg 2+ is transported into the cell via the transporter SPBC27B12.12c (Uz & Sarikaya, 2016). When the extracellular Mg 2+ concentration is low, the intracellular Mg 2+ concentration slightly decreases (Figure 3c).…”

“…Some studies have revealed the effects of the Mg 2+ transporter Alr1 in budding yeast (Lim et al, 2011). The effects of Mg 2+ on the growth and the cell cycle and mitotic spindle of fission yeast have also been reported (Sarikaya et al, 2006;Uz & Sarikaya, 2016;Walker & Duffus, 1980). However, knowledge of the molecular mechanisms that regulate the response to environmental Mg 2+ in Schizosaccharomyces pombe is limited.…”