How to make a spore

Step 1: Formation of the Prospore Membrane

Formation of a prospore membrane attached to the spindle pole requires (1) the construction on the spindle pole body of a specialized membrane organizing center, the meiotic outer plaque and (2) the redirection and coalescence of secretory vesicles onto the meiotic outer plaque to form the incipient prospore membrane.

Step 2 Membrane Growth

Prospore membrane expansion is driven by the continued delivery and fusion of secretory vesicles. Growth in the proper shape and direction is maintained by two multiprotein complexes; one that contains intermediate filament proteins called Septins (3), and a second termed the leading edge complex (4).

Step 3 Prospore Membrane Closure

Fusion of the "ends" of the prospore membrane with completely encloses the daughter nucleus and creates two distinct lipid bilayers from the single, continuous membrane present as the prospore membrane grows. After closure the prospore is now an autonomous cell, thus prospore membrane closure is equivalent to cytokinesis.

Step 4 Spore Wall Formation

After closure of the prospore membrane, spore wall construction begins in the lumen between the two membranes derived from the prospore membrane . The spore wall is a stratified extracellular matrix with three distinct polysaccharide layers mannan, glucan, and chitosan and an outermost layer that contains dityrosine. The layers are laid down sequentially from innermost to outermost. The outermost layers confer much of the stress resistant properties of the spore.