Schizosaccharomyces pombe

S. pombe is the other commonly studied yeast first isolated from Pombe (an East African millet beer). S. pombe is a unicellular eukaryote with a genome size of 14 Mb containing approximately 7000 genes arranged in three distinct chromosomes. As with S. cerevisiae, it is manipulated in a similar manner as bacterial cells. S. pombe grows in liquid or on plates at 25-35°C with optimal growth at 35°C. It has a doubling time of 2-3 hours when grown on rich media (YES) and 2.2-4 hours when grown on minimal media (EMM, for example). At 35°C there is little difference in growth rate between rich and minimal media. S. pombe has two mating types, h+ and h- and is stable both as haploid and diploid. Auxotrophic markers commonly used with S. pombe are: ade, glu, his leu, lys and ura. Conjugation and sporulation can only take place when starved for nutrients and homologous recombination is less efficient compared to S. cerevisiae. Unlike S. cerevisiae, S. pombe has a typical eukaryotic cell cycle with discrete G1, S, G2 and M phases. Furthermore, its chromosome structure and RNA processing are closer to mammalian cells than S. cerevisiae. As such, a conserved function between the two organisms strongly indicate the existence of an equivalent function in other eukaryotes. BIO 101 offers media for all S. pombe manipulations.

Cell storage and revival As with S. cerevisiae, S. pombe can be stored for several weeks to months at 4°C on plates or slants and indefinitely in 15% glycerol at, -70°C. Revive by scraping some of the cells off the frozen surface, streak onto plates, and incubate at 25-35°C until growth is observed.

The genome of S. pombe is the subject of an active multi-site sequencing effort. Information on this and other S. pombe subjects can be found at websites: http://www2.bio.uva.nl/pombe/ and http://flosun.salk.edu/~forsburg/ and associated links.