Jeffrey Segall's Lab

Yeast Movies

The baker's yeast, Saccharomyces cerevisae is an extremely well characterized genetic system. This primitive eukaryote, although it does not move, can show orientation behavior. During the mating process, mating partners of opposite mating types release mating factors. In response to gradients of these mating factors, yeast polarize the growth of their mating processes as shown below.

Polarization of mating processes (2.3 Mb)

In response to alpha mating factor released from the pipet, a mating type cells polarize their projections to form cigar-shaped shmoos. Note that good orientation towards the micropipet only occurs in response to low concentrations of mating factor, and at these concentrations, this type of shmoo is formed.

Polarization of the cell division apparatus (2.2 Mb)

Orientation of the shmoo towards the micropipet also determines the site of cell division if the source of mating factor is removed. In this case, the pipet was removed after the cells had oriented and in consequence, the cells started budding from the tip growing towards the micropipet.