Telomeric Repeats Act As Nucleosome-disfavouring Sequences in Vivo
Overview
Affiliations
Telomeric DNAs consist of tandem repeats of G-clusters such as TTAGGG and TG1-3, which are the human and yeast repeat sequences, respectively. In the yeast Saccharomyces cerevisiae, the telomeric repeats are non-nucleosomal, whereas in humans, they are organized in tightly packaged nucleosomes. However, previous in vitro studies revealed that the binding affinities of human and yeast telomeric repeat sequences to histone octamers in vitro were similar, which is apparently inconsistent with the differences in the human and yeast telomeric chromatin structures. To further investigate the relationship between telomeric sequences and chromatin structure, we examined the effect of telomeric repeats on the formation of positioned nucleosomes in vivo by indirect end-label mapping, primer extension mapping and nucleosome repeat analyses, using a defined minichromosome in yeast cells. We found that the human and yeast telomeric repeat sequences both disfavour nucleosome assembly and alter nucleosome positioning in the yeast minichromosome. We further demonstrated that the G-clusters in the telomeric repeats are required for the nucleosome-disfavouring properties. Thus, our results suggest that this inherent structural feature of the telomeric repeat sequences is involved in the functional dynamics of the telomeric chromatin structure.
Structural biology of shelterin and telomeric chromatin: the pieces and an unfinished puzzle.
Hu H, Yan H, Nguyen T Biochem Soc Trans. 2024; 52(4):1551-1564.
PMID: 39109533 PMC: 7617103. DOI: 10.1042/BST20230300.
Exploring TRF2-Dependent DNA Distortion Through Single-DNA Manipulation Studies.
Zhao X, Vogirala V, Liu M, Zhou Y, Rhodes D, Sandin S Commun Biol. 2024; 7(1):148.
PMID: 38310140 PMC: 10838314. DOI: 10.1038/s42003-024-05838-x.
The shelterin component TRF2 mediates columnar stacking of human telomeric chromatin.
Wong S, Soman A, Korolev N, Surya W, Chen Q, Shum W EMBO J. 2024; 43(1):87-111.
PMID: 38177309 PMC: 10883271. DOI: 10.1038/s44318-023-00002-3.
Forsyth R, Krenacs T, Athanasou N, Hogendoorn P Cancers (Basel). 2021; 13(20).
PMID: 34680268 PMC: 8534144. DOI: 10.3390/cancers13205119.
Chemical map-based prediction of nucleosome positioning using the Bioconductor package nuCpos.
Kato H, Shimizu M, Urano T BMC Bioinformatics. 2021; 22(1):322.
PMID: 34120589 PMC: 8201924. DOI: 10.1186/s12859-021-04240-2.