Centric heterochromatin

Mitoticchromosome
Mitoticchromosome

Centric heterochromatin, a variety of heterochromatin, is a tightly packed form of DNA. Centric heterochromatin is a constituent in the formation of active centromeres in most higher-order organisms; the domain exists on both mitotic and interphase chromosomes.[1]

Centric heterochromatin is usually formed on alpha satellite DNA in humans; however, there have been cases where centric heterochromatin and centromeres have formed on originally euchromatin domains lacking alpha satellite DNA; this usually happens as a result of a chromosome breakage event and the formed centromere is called a neocentromere.[1]

Centric heterochromatin domains are flanked by pericentric heterochromatin.[1]

Transcription

Despite its compact state, centromeric satellite DNA is transcribed at low levels into non-coding RNAs, which help maintain centromeric heterochromatin and recruit centromere and kinetochore proteins.[2][3] In human cells, centromeric transcription continues through early G1, when CENP-A is deposited, and experiments in Drosophila cells indicate that short transcriptional inhibition impairs stable centromeric CENP-A incorporation.[2][4] Both reduced and excessive centromeric transcription are associated with chromosome-segregation defects.[2][3]

See also

References

  1. 1 2 3 Molecular Biology of the Cell. pp. 229–231. ISBN 978-0-8153-4105-5.
  2. 1 2 3 "Centromere and Pericentromere Transcription: Roles and Regulation ... in Sickness and in Health". Frontiers in Genetics. 2018.
  3. 1 2 "Roles for Non-coding RNAs in Spatial Genome Organization". Frontiers in Cell and Developmental Biology. 2019.
  4. ↑ "Centromere transcription allows CENP-A to transit from chromatin association to stable incorporation" (PDF). Journal of Cell Biology. 2018.
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