Schizosaccharomyces pombe

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A Microbial Biorealm page on the genus Schizosaccharomyces pombe

Classification

Higher order taxa

Superkingdom: Eukaryota

Kingdom: Fungi

Phylum: Ascomycota

Subphylum: Dikarya

Subphylum: Taphrinomycotina

Class: Schizosaccharomycetes

Order: Schizosaccharomycetales

Family: Schizosaccharomycetaceae

Genus: Schizosaccharomyces

Species

Schizosaccharomyces pombe

Also known as: Schizosaccharomyces malidevorans

Description and significance

The fission yeast Schizosaccharomyces pombe is a unicellular eukaryote that is rod shaped. They measure approximately 2 to 3 microns in diameter and 7 to 14 microns in length (1). S. pombe is usually found in sugar-containing fermentations of alcohol from the subtropical regions (2).

Even though its origin dates back to quite a long time ago, it was not widely known before the 1890’s. It was discovered in 1893 when a group working in a Brewery Association Laboratory in Germany was looking at sediment found in millet beer imported from East Africa that gave it an unsavory acidic taste (1). P. Lindner was the first to describe Schizosaccharomyces pombe. He chose as its epithet the Swahili word for beer, pombe (2). It was identified as yeast, and it became known as the fission yeast because it reproduces by means of fission unlike its relative Saccharomyces. The name Schizosaccharomyces was assigned to it because Schizo- means “different,” which had been previously used to describe other fission species.

The sequencing of its genome was significant since S. pombe is a single-celled living archiascomycete fungus that shares many features with cells of more complicated eukaryotes (3). Researchers have identified fifty genes of S. pombe associated with human diseases including cystic fibrosis, hereditary deafness, and diabetes (3). Researchers state that the largest group of human disease-related genes are those implicated in cancer. There are 23 such genes, and they are involved in DNA damage and repair, checkpoint controls, and the cell cycle. All these processes are involved with maintaining genomic stability (3). These discoveries are important because it will allow researchers to find out more about the evolution of one-celled and multi-celled eukaryotic organisms compared to others such as bacteria, which do not have nucleated cells. Further analyses and comparisons should reveal which genes define eukaryotic cells and the transition from one-celled to multi-celled organisms (3).

Genome structure

S. pombe was the sixth organism with a nucleus to have its genome sequenced. S. pombe has a small and compact genome. Its genome contains 13.8 million base pairs distributed among chromosomes I (5.7 Mb), II (4.6 Mb) and III (3.5 Mb) and 4,824 genes. It has the lowest number of protein-coding genes yet identified in a free-living eukaryotic cell (1). The 3 chromosomes are linear, but circular chromosome formation has been observed in a fission yeast mutants. If the S. pombe lose the simple repeats at the very ends of the chromosomes as well as much of the subtelomeric TAS elements, it will fuse end to end to generate circular chromosomes (4). The three centromeres are 35, 65, and 110 kb long for chromosomes I, II, and III respectively. This leaves about 12.5 Mb of unique sequence.

Cell structure and metabolism

Describe any interesting features and/or cell structures; how it gains energy; what important molecules it produces.

Ecology

Describe any interactions with other organisms (included eukaryotes), contributions to the environment, effect on environment, etc.

Pathology

The yeast 'Schizosaccaromyces pombe' is a harmless, rapidly growing eukaryote. Therefore, there are no pathologies associated with this particular organism.

Application to Biotechnology

Does this organism produce any useful compounds or enzymes? What are they and how are they used?

Current Research

Enter summaries of the most recent research here--at least three required

References

[Sample reference] Takai, K., Sugai, A., Itoh, T., and Horikoshi, K. "Palaeococcus ferrophilus gen. nov., sp. nov., a barophilic, hyperthermophilic archaeon from a deep-sea hydrothermal vent chimney". International Journal of Systematic and Evolutionary Microbiology. 2000. Volume 50. p. 489-500.

Edited by student of Rachel Larsen