Switch-like reprogramming of gene expression after fusion of multinucleate plasmodial cells of two Physarum polycephalum sporulation mutants

Gene expression kinetics in individual plasmodial cells reveal alternative programs of differential regulation during commitment and differentiation

“…); (iii) at threshold stimulus intensity, the decision of a plasmodium to sporulate is taken stochastically and is all‐or‐none for any given plasmodium (Starostzik & Marwan , , ); (iv) two plasmodia, each carrying a different sporulation‐suppressing mutation, one plasmodium stimulated the other not, self‐synchronize even when the new gene expression pattern is established in a switch‐like manner (Walter et al . ). We conclude that in a plasmodium, unlike as in a mononucleate eukaryotic cell of typical volume, stochasticity of signaling and gene expression in terms of molecular noise is dampened due to the large cytoplasmic volume of the plasmodium, which may facilitate the system‐wide identification of molecular switches and the analysis of bifurcation phenomena related to the control of commitment and differentiation.…”

“…Hence one would expect that the streaming cytoplasm dampens stochasticity of transcription, translation, and of biochemical processes including signaling. The validity of these assumptions is supported by the following experimental findings: (i) plasmodial nuclei are naturally synchronous in proceeding through the cell cycle (Rusch et al 1966;Sachsenmaier et al 1972); (ii) nuclear populations of two plasmodia that are in different phases of the cell cycle self-synchronize immediately after fusion of the two plasmodia (Rusch et al 1966;Sachsenmaier et al 1972); (iii) at threshold stimulus intensity, the decision of a plasmodium to sporulate is taken stochastically and is all-or-none for any given plasmodium (Starostzik & Marwan 1994, 1995a, 1998; (iv) two plasmodia, each carrying a different sporulation-suppressing mutation, one plasmodium stimulated the other not, self-synchronize even when the new gene expression pattern is established in a switch-like manner (Walter et al 2013). We conclude that in a plasmodium, unlike as in a mononucleate eukaryotic cell of typical volume, stochasticity of signaling and gene expression in terms of molecular noise is dampened due to the large cytoplasmic volume of the plasmodium, which may facilitate the system-wide identification of molecular switches and the analysis of bifurcation phenomena related to the control of commitment and differentiation.…”

Developmental switching inPhysarum polycephalum: Petri net analysis of single cell trajectories of gene expression indicates responsiveness and genetic plasticity of the Waddington quasipotential landscape

“…Plasmodial cells of strain PHO3 were starved for six days and exposed to a far-red light stimulus. Before and at different time points after the stimulus, a sample was taken from each plasmodium to analyse the expression pattern of a set of genes that are up-or down-regulated in the wild-type in association with developmental switching [36,46] ( Fig 1B). The remainder of the plasmodium was incubated until the next day to see whether sporulation had occurred.…”

“…The plasmodium is a giant single cell that can be grown to arbitrary size. Because the myriad of nuclei that are suspended in its cytoplasm display natural synchrony in cell cycle regulation and differentiation [31][32][33][34][35][36], the plasmodium provides a source from which macroscopic samples of homogeneous cell material can be repeatedly taken in order to analyse how the molecular components change as a function of time. To set a defined starting point, sporulation of a starving plasmodium can be triggered by a short pulse of far-red light which switches a phytochrome photoreceptor into its active state [37][38][39].…”

Study of morphological and mechanical features of multinuclear and mononuclear SW480 cells by atomic force microscopy

“…A tumor cell, often contains more nuclei (Lu & Kang, ; Sheehy, Wakonig‐Vaartaja, Winn, & Clarkson, ; Zhu & Friedland, ). The fusion of plasmodia (Beno et al, ; Ming, Dong, Zhong, Grevelding, & Jiang, ; Walter, Hoffmann, Ebeling, Haas, & Marwan, ), closed mitosis (Guffei et al, ; S. Kim et al, ) and cell division (Cool et al, ; Kuroda & Furuyama, ) can lead to the coexistence of different nuclei and formation of multinuclear cells (Papadimitriou, Sforsina, & Papaelias, ). Studies have shown that multinuclear cells commonly exist in tumors and they are a key character for the diagnosis of cancer (Knecht et al, ; Knecht, Sawan, Lichtensztejn, Lichtensztejn, & Mai, ; W. Zhang, Lin, Ramoth, Fan, & Fidler, ).…”