1. Rearrangement of macronucleus chromosomes correspond to TAD-like structures of micronucleus chromosomes in Tetrahymena thermophila
- Author
-
Tengfei Hu, Ruoyu Wang, Jun Cao, Xiaoyuan Song, Simo V. Zhang, Hong Jiang, Qianlan Xu, and Zhengyu Luo
- Subjects
0303 health sciences ,Macronucleus ,Cohesin complex ,biology ,Somatic cell ,Tetrahymena ,Chromosome ,biology.organism_classification ,Cell biology ,Chromatin ,03 medical and health sciences ,0302 clinical medicine ,Meiosis ,Centromere ,Genetics ,030217 neurology & neurosurgery ,Genetics (clinical) ,030304 developmental biology - Abstract
The somatic macronucleus (MAC) and germline micronucleus (MIC) of Tetrahymena thermophila differ in chromosome numbers, sizes, functions, transcriptional activities, and cohesin complex location. However, the higher-order chromatin organization in T. thermophila is still largely unknown. Here, we explored the higher-order chromatin organization in the two distinct nuclei of T. thermophila using the Hi-C and HiChIP methods. We found that the meiotic crescent MIC has a specific chromosome interaction pattern, with all the telomeres or centromeres on the five MIC chromosomes clustering together, respectively, which is also helpful to identify the midpoints of centromeres in the MIC. We revealed that the MAC chromosomes lack A/B compartments, topologically associating domains (TADs), and chromatin loops. The MIC chromosomes have TAD-like structures but not A/B compartments and chromatin loops. The boundaries of the TAD-like structures in the MIC are highly consistent with the chromatin breakage sequence (CBS) sites, suggesting that each TAD-like structure of the MIC chromosomes develops into one MAC chromosome during MAC development, which provides a mechanism of the formation of MAC chromosomes during conjugation. Overall, we demonstrated the distinct higher-order chromatin organization in the two nuclei of the T. thermophila and suggest that the higher-order chromatin structures may play important roles during the development of the MAC chromosomes.
- Published
- 2020