NORs on human acrocentric chromosome p-arms are active by default and can associate with nucleoli independently of rDNA
Abstract
A detailed description of how the genome is organized within the human nucleus is a major research goal. Nucleolar organizer regions (NORs) comprising ribosomal DNA (rDNA) arrays are located on the p-arms of the five human acrocentric chromosomes. Here we characterize the rules of engagement between NORs and nucleoli. We reveal variation in rDNA distribution, with some primary cell lines containing as many as four acrocentrics devoid of rDNA. We establish the default status of NORs as active and show that acrocentric p-arms devoid of rDNA retain nucleolar association potential. Based on our data, we propose that in diploid human cells, all 10 acrocentric chromosomes are nucleolar-associated, with involvement of non-rDNA sequences buffering against variable rDNA distribution.
- Publication:
-
Proceedings of the National Academy of Science
- Pub Date:
- May 2020
- DOI:
- 10.1073/pnas.2001812117
- Bibcode:
- 2020PNAS..11710368V