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Extrachromosomal rDNA circles (aka ERC) are self replicating sequences of ribosomal DNA (rDNA) found in a strain of yeast, Saccharomyces cerevisiae, and are suggested to contribute to their aging and found in their aged cells.[1] [2][3] By intra-molecular homologous recombination of the chromosome, extrachromosomal circular DNA (eccDNA) are formed as well as ERCs.[4][5][6]
ERCs in yeast strains
[edit]The Sgs1 gene mutations of yeast were shown to have accelerated aging on their mother cells, suggesting they additional function to cellular senescence.[7] Additionally, ERCs accumulate in old cells and mutations of Sgs1 were found to increase this accumulation, leading to the idea that ERCs lead to shorter lifespan of cells.[8] The ERC accumulate in the mother cell during the budding process.[2] Sinclair et al. mentioned a suggested common mechanism between the Sgs1 and WRN genes since they both had age related effects on yeast and human aging respectively.[8][9][10][11]
Borghouts et al, determined that the generation ERCs negatively influence the life spans of grande and petite yeast strains[12].
ERCs in Xenopus Laevis
[edit]Circular extrachromosomal DNA are not only found in yeast but other eukaryotic organisms.[13][14] Cohen et al. developed a regulated formation of eccDNA in preblastua Xenopus embryos. They determined from 2D electrophoresis analysis that eccDNA decreased with the degradation of amplified rDNA. Additionally, with an excess of rDNA sequences, they are not prone to generating circular extrachromosomes from random events of breakage and ligation.[15]
ERCs in retrograde response
[edit]Poole et al. provided a model that resolves the role of retrograde response in lifespan. They depict a proces in which ERC production occurs and shortens lifespan in the TAR1 gene[16].
See also
[edit]References
[edit]- ^ Sinclair DA, Guarente L (1997). "Extrachromosomal rDNA circles--a cause of aging in yeast". 91 (7): 1033–42. doi:10.1016/S0092-8674(00)80493-6. PMID 9428525.
{{cite journal}}: Cite journal requires|journal=(help) - ^ a b Nyström (2007). "A Bacterial Kind of Aging".
- ^ Encyclopedia of Genetics, Genomics, Proteomics and Informatics. Springer Netherlands. 2008. pp. 629–629. doi:10.1007/978-1-4020-6754-9_5501. ISBN 9781402067532.
- ^ Cohen at al. (2003). "Extrachromosomal Circular DNA of Tandemly Repeated Genomic Sequences in Drosophila".
{{cite journal}}: Cite journal requires|journal=(help) - ^ "extrachromosomal rDNA circle accumulation involved in replicative cell aging | SGD". www.yeastgenome.org. Retrieved 2017-10-20.
- ^ "extrachromosomal rDNA circle | SGD". www.yeastgenome.org. Retrieved 2017-10-20.
- ^ Sinclair, D. A.; Mills, K.; Guarente, L. (1997-08-29). "Accelerated aging and nucleolar fragmentation in yeast sgs1 mutants". Science (New York, N.Y.). 277 (5330): 1313–1316. ISSN 0036-8075. PMID 9271578.
- ^ a b Sinclair, David A.; Mills, Kevin; Guarente, Leonard (1997-08-29). "Accelerated Aging and Nucleolar Fragmentation in Yeast sgs1 Mutants". Science. 277 (5330): 1313–1316. doi:10.1126/science.277.5330.1313. ISSN 0036-8075. PMID 9271578.
- ^ Strehler, Bernard L. (1986-01-01). "Genetic instability as the primary cause of human aging". Experimental Gerontology. 21 (4): 283–319. doi:10.1016/0531-5565(86)90038-0.
- ^ Adamstone, F. B.; Taylor, A. B. (1977-12-01). "Nucleolar reorganization in cells of the kidney of the rat and its relation to aging". Journal of Morphology. 154 (3): 459–477. doi:10.1002/jmor.1051540306. ISSN 1097-4687.
- ^ Weinstein, Martha E.; Mukherjee, Asit B. "Culture media variation as related to in vitro aging of human fibroblasts: II. effects on nucleolar number/cell, volume/nucleolus and total nucleolar volume/cell". Mechanisms of Ageing and Development. 42 (3): 215–227. doi:10.1016/0047-6374(88)90048-6.
- ^ Borghouts, Corina; Benguria, Alberto; Wawryn, Jaroslaw; Jazwinski, S. Michal (2004-02-01). "Rtg2 Protein Links Metabolism and Genome Stability in Yeast Longevity". Genetics. 166 (2): 765–777. doi:10.1534/genetics.166.2.765. ISSN 0016-6731. PMID 15020466.
- ^ Cohen, Sarit; Menut, Sophie; Méchali, Marcel (October 1999). "Regulated Formation of Extrachromosomal Circular DNA Molecules during Development in Xenopus laevis". Molecular and Cellular Biology. 19 (10): 6682–6689. ISSN 0270-7306. PMID 10490607.
- ^ Gaubatz, James W. (1990-09-01). "Extrachromosomal circular DNAs and genomic sequence plasticity in eukaryotic cells". Mutation Research/DNAging. 237 (5): 271–292. doi:10.1016/0921-8734(90)90009-G.
- ^ Cohen, Sarit; Menut, Sophie; Méchali, Marcel (October 1999). "Regulated Formation of Extrachromosomal Circular DNA Molecules during Development in Xenopus laevis". Molecular and Cellular Biology. 19 (10): 6682–6689. ISSN 0270-7306. PMID 10490607.
- ^ Poole, Anthony M.; Kobayashi, Takehiko; Ganley, Austen R. D. (2012-09-01). "A positive role for yeast extrachromosomal rDNA circles?". BioEssays. 34 (9): 725–729. doi:10.1002/bies.201200037. ISSN 1521-1878.
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