Correlates of developmental cell death in Dictyostelium discoideum

Centre for Cellular and Molecular Biology, Bhaganagar, Telangana, India
Differentiation (Impact Factor: 3.44). 09/2002; 70(6):272-81. DOI: 10.1046/j.1432-0436.2002.700605.x
Source: PubMed


We have studied the correlates of cell death during stalk cell differentiation in Dictyostelium discoideum. Our main findings are four. (i) There is a gradual increase in the number of cells with exposed phosphatidyl serine residues, an indicator of membrane asymmetry loss and increased permeability. Only presumptive stalk cells show this change in membrane asymmetry. Cells also show an increase in cell membrane permeability under conditions of calcium-induced stalk cell differentiation in cell monolayers. (ii) There is a gradual fall in mitochondrial membrane potential during development, again restricted to the presumptive stalk cells. (iii) The fraction of cells showing caspase-3 activity increases as development proceeds and then declines in the terminally differentiated fruiting body. (iv) There is no internucleosomal cleavage of DNA, or DNA fragmentation, in D. discoideum nor is there any calcium- and magnesium-dependent endonucleolytic activity in nuclear extracts from various developmental stages. However, nuclear condensation and peripheralization does occur in stalk cells. Thus, cell death in D. discoideum shows some, but not all, features of apoptotic cell death as recognized in other multicellular systems. These findings argue against the emergence of a single mechanism of 'programmed cell death (PCD)' before multicellularity arose during evolution.

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Available from: Vidyanand Nanjundiah, Jan 19, 2016
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    • "Under such conditions, detailed below, Dictyostelium cells differentiate as a monolayer from vegetative to " stalk " vacuolated dead cells [28] [29] [30] (Fig. 2). While most of the work reviewed below on Dictyostelium cell death in vitro comes from our laboratory, the laboratory of Prof. R.R. Kay and other laboratories (such as [31] [32] [33] [34] [35]) contributed studies on cell death in this system. Monolayer experiments were most often done using the D. discoideum axenic strain HMX44A, subcloned from the mutant strain HM44 [36]. "
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    • "Lam et al., 2007). Although in this chapter we usually refer to cell death as studied in our laboratory, other groups have also studied cell death in Dictyostelium, often in non-developmental contexts (Arnoult et al., 2001; Katoch and Begum, 2003; Kawli et al., 2002; Li et al., 2000; Schaap et al., 1996; Tatischeff et al., 2001). "
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    • "During development of the stalk, many features of the dying cells mimic those observed during mammalian apoptosis [23] [24]. Whether cells live or die can be influenced by genetic factors, providing additional support for the notion that stalk cell death is programmed [25] [26] [27] [28] [29]. "
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