A universal and unquestioned characteristic of eukaryotic cells is that the genome is divided into multiple chromosomes and encapsulated in a single nucleus. However, the underlying mechanism to ensure such a configuration is unknown. Here we provide evidence that pericentromeric satellite DNA, which is often regarded as junk, is a critical constituent of the chromosome, allowing the packaging of all chromosomes into a single nucleus. We show that the multi AT-hook satellite DNA binding proteins, D. melanogaster D1 and mouse HMGA1, play an evolutionarily conserved role in bundling pericentromeric satellite DNA from heterologous chromosomes into 'chromocenters', a cytological association of pericentromeric heterochromatin. Defective chromocenter formation leads to micronuclei formation due to budding from the interphase nucleus, DNA damage and cell death. We propose that chromocenter and satellite DNA serves a fundamental role in encapsulating the full complement of the genome within a single nucleus, the universal characteristic of eukaryotic cells.
- Yukiko M Yamashita
- Yukiko M Yamashita
- Madhav Jagannathan
The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.
- K VijayRaghavan, National Centre for Biological Sciences, Tata Institute of Fundamental Research, India
© 2018, Jagannathan et al.
This article is distributed under the terms of the Creative Commons Attribution License permitting unrestricted use and redistribution provided that the original author and source are credited.
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Structures known as chromocenters, comprising satellite DNA and proteins such as D1 or HMGA1, help to contain DNA inside the nucleus between cell divisions.
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