Yoshinori Ohsumi and Yeast Deletion Library


Yoshinori Ohsumi won 2016 Nobel Prize in Physiology or Medicine. He solved mechanisms of autophagy, the process named as cells eat their own organelles; it can be called also recycle system for cells. (1)
Yoshinori Ohsumi formed strain for engineered yeast cells and used starvation to detect autophagosomes until accumulation. If accumulation doesn’t appearance, the gene engineered is under inactivation at a certain point of autophagy mechanisms. Ohsumi generated many random mutations by chemicals onto yeast genes, and then these mutated genes have included genes being responsible at autophagy. By using this method, he solved mechanism. (1)
Yeast Deletion Library is to build a library including information of locations and functions of genome of yeast. It was started in 1996. As a Saccharomyces Genome Project, it was announced for first time and released more than 6000 open frames, ORF; in Cerevisiae genome. And we could get this information from phenotypic mutations directly. However scientists in these days haven’t known functions of many ORFs. PCR-based gene deletion method was a better way for determine ORF functions. It achieves start and stop codon of each ORF for producing sequence of yeast cells. Scientists used for various tags and methods for determining functions of genes. We had essential genes for growth anymore under certain medium. This kind of information made our studies for yeast cells easier. In 2000, Yeast Knock-out (YKO) deletion was effective way to learn yeast genome better. We used available yeast genome with this method. Today the project was accomplished. We know all genome of yeast. (2)
Human cells and yeast cells are eukaryotic, so their homology is so similar. Fundamental cellular processes such as the cell cycle, DNA replication, recombination, cell division, and metabolism are same. Many proteins important in human biology were first discovered by studying their homologues in yeast; these proteins include cell cycle proteins, signalling, and protein-processing enzymes. Cell cycle is similar too. Yeasts can have diploid or haploid according to conditions. Human cells can also be but they can be just formed according to specialized type of cell. (3)

POLA1 is a gene having homology between yeast and human genome. Function of this gene is synthesis of the catalytic subunit of DNA polymerase and to form alpha DNA polymerase complex with other subunits. The catalytic subunits have an important and essential role in the initiation of DNA replication. (4, 5)
References:
1-(https://www.nobelprize.org/nobel_prizes/medicine/laureates/2016/press.html)
2- (http://www-sequence.stanford.edu/group/yeast_deletion_project/deletions3.html)
3- David Botstein, Steven A. Chervitz, and J. Michael Cherry. Science. 1997 Aug 29. Yeast as a Model Organism (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3039837/)
4- http://genomics.senescence.info/genes/entry.php?hgnc=POLA1
5- https://www.ncbi.nlm.nih.gov/gene/5422

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