Impact of embryo size on apoptosis in C. elegans

During <i>C. elegans</i> development 131 somatic cells reproducibly undergo programmed cell death. Many of these 131 cells 'programmed to die' are the smaller daughter of a neuroblast that divides asymmetrically and die through apoptosis. To determine whether cell size impacts the ability of cells programmed to die to undergo apoptosis, we increased or decreased embryo size by RNA interference-mediated knock-down of the genes <i>C27D9.1</i> or <i>ima-3</i> , respectively. We found that in apoptosis-compromised genetic backgrounds, <i>C27D9.1</i> ( <i>RNAi</i> ) enhances and <i>ima-3</i> ( <i>RNAi</i> ) partially suppresses inappropriate survival of cells programmed to die. This supports the notion that in <i>C. elegans</i> embryos, an increase in cell size compromises and a decrease in cell size promotes the ability of cells programmed to die to undergo apoptosis.