Formation of multinuclear cells induced by dimethyl sulfoxide: inhibition of cytokinesis and occurrence of novel nuclear division in Dictyostelium cells.

Abstract

Our previous studies showed that 10% dimethyl sulfoxide (DMSO) induces the formation of actin microfilament bundles in the cell nucleus together with the dislocation of cortical microfilaments from the plasma membrane . The present study investigated the effects of DMSO on diverse activities mediated by cellular microfilaments as the second step toward assessing potential differences between nuclear and cytoplasmic actins of Dictyostelium mucoroides. DMSO was found to reversibly inhibit cell-to-glass as well as cell-to-cell adhesion, cell locomotion, and cell multiplication, whereas cytoplasmic streaming and phagocytosis were not obviously inhibited .Also, 5% DMSO inhibited cytokinesis but did not totally inhibit cell growth thus leading to the development of giant cells more than 10 times larger than normal cells. Transmission electron microscopy using serial thin sections showed the occurrence of multinucleation in the DMSO-induced giant cells. After the removal of DMSO, the giant multinuclear cells underwent multiple cytoplasmic cleavage producing normal-sized mononuclear cells.The nuclear division in the DMSO-induced giant cells was unique in that no spindle microtubules were formed, and vesicles appeared inside the nucleus forming a transverse partition of the nuclear envelope . The presence of actin filaments in those nuclei was demonstrated by a binding study with skeletal muscle myosin subfragment-1, and their possible involvement in this mode of nuclear division is discussed .Since Ryser (30) first found microfilaments in the nuclei of Physarum polycephalum, considerable evidence showing the localization of actin in the cell nucleus has accumulated. Ultrastructural studies have proven the existence of actin filaments in mitotic cell nuclei of crane fly (3) and locust (17) testes. Actin has also been identified in nuclear as well as chromosome nonhistone proteins in rat liver (8), P. polycephalum (19), and Dictyostelium discoideum (22). We found that dimethyl sulfoxide (DMSO) induces the formation of huge microfilament bundles of actin in the Dictyostelium nucleus (13). We have shown that this formation of nuclear bundles could also be induced in interphase nuclei of Amoeba proteus, HeLa cells

Filopodelike projections induced with dimethyl sulfoxide and their relevance to cellular polarity in Dictyostelium.

“…Since finding the prominent effect of DMSO of inducing nuclear actin bundle formation (15,16), we have performed some studies on cell motility by using this agent as a chemical probe with which to manipulate the cellular microfilaments (17,18). Our preliminary finding that the cortical microfdaments became dislocated from the plasma membrane by the action of DMSO encouraged us to do the present study to gain insight into the supramolecular mechanism of cell motile activities.…”

“…Previously, we have shown that DMSO acts on Dictyosteliurn cells to dislocate the cortex microfflaments from the plasma membrane, resulting in cell rounding up and a cessation of cytoplasmic streaming (17). We have also revealed that 5% DMSO impedes the cytokinesis of this organism in a growing condition and that conspicuous multinuclear cells are produced (18). In this study, we used DMSO as a chemical agent to manipulate the microftlament system of the cortex layer to assess its possible roles in cell structure and motile activities.…”

“…FIGURE 4 The SDS PAGE of D. rnucoroides membrane fractions. [A] The membrane fractions were prepared according to Spudich (25), followed by the SDS PAGE on 5-15% linear gradient gels containing 0.1% SDS according to Laemmli(18). 50 gg of the proteins was charged on each slot.…”

Structure and function of the cytoskeleton of a Dictyostelium myosin-defective mutant.

“…The possible role of myosin during mitosis has been debated for many years. Because the disruption of the mhcA gene gives rise to a population of multinucleated cells, we were interested m study whether the multinucleation results from normal mitosis (30) or from abnormal nuclear division (18). We found that the hmm cells were capable of forming spindles.…”

<b>TWO DISTINCT COMPONENTS OF TUBULIN TRANSPORT IN SENSORY AXONS OF THE RAT RECOGNISED BY DIMETHYL SULFOXIDE </b><b>TREATMENT </b>

“…(DMSO), frequently used as a solvent for water-insoluble drugs, is known to have effects on the cytoskeletal proteins. When included in culture medium, it causes the disappearance of cortical microfilaments and the formation of actin bundles in the nucleus, leading to cessation of cytokinesis and cell division (4)(5)(6)19). DMSO also induces the in vitro assembly of tubulin in the absence of associated proteins and stabilises the polymerised microtubules (8,18).…”