Schizosaccharomyces pombe
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
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Ecology
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Pathology
The yeast 'Schizosaccaromyces pombe' is a harmless, rapidly growing eukaryote. Therefore, there are no pathologies associated with this particular organism.
Application to Biotechnology
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Current Research
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References
Edited by student of Rachel Larsen
