Double minute

Double minutes are small fragments of extrachromosomal DNA, which have been observed in a large number of human tumors including breast, lung, ovary, colon, and most notably, neuroblastoma. They are a manifestation of gene amplification as a result of chromothripsis,[1] during the development of tumors, which give the cells selective advantages for growth and survival. This selective advantage is as a result of double minutes frequently harboring amplified oncogenes and genes involved in drug resistance. Double minutes, like actual chromosomes, are composed of chromatin and replicate in the nucleus of the cell during cell division. Unlike typical chromosomes, they are composed of circular fragments of DNA, up to only a few million base pairs in size and contain no centromere or telomere. Further to this, they often lack key regulatory elements, allowing genes to be constitutively expressed. Recently, some research groups are re-branding double minutes as ecDNA.[2]

See also

References
  1. Stephens PJ, Greenman CD, Fu B, et al. (2011). "Massive Genomic Rearrangement Acquired in a Single Catastrophic Event during Cancer Development". Cell. 144 (1): 27–40. doi:10.1016/j.cell.2010.11.055. PMC 3065307. PMID 21215367.
  2. Wu, Sihan; Turner, Kristen M.; Nguyen, Nam; Raviram, Ramya; Erb, Marcella; Santini, Jennifer; Luebeck, Jens; Rajkumar, Utkrisht; Diao, Yarui; Li, Bin; Zhang, Wenjing (November 2019). "Circular ecDNA promotes accessible chromatin and high oncogene expression". Nature. 575 (7784): 699–703. Bibcode:2019Natur.575..699W. doi:10.1038/s41586-019-1763-5. ISSN 1476-4687. PMC 7094777. PMID 31748743.


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