Counting spores

During meiosis, yeast cells use their spindle pole bodies (SPBs), their equivalent of centrosomes, as the basis for building a structure called the meiotic plaque. The plaque in turn forms the basis for forming a spore. On page 627, Taxis et al. present a model in which nutrition availability determines how many meiotic plaques and thus spores are formed.Three major protein components comprise the meiotic plaque, which is the site of assembly of spore membranes. If one of the three proteins is missing, plaques do not form and spores are not produced.

By monitoring the formation of meiotic plaques under different conditions, the team found a correlation between the amount of plaque constituents synthesized, the number of plaques generated, and nutrient abundance. Once proteins joined the plaque structure, they seemed to be locked in...