Centromeric islands constrain CENP-A domain size and position
- 1University of Connecticut
Abstract
Centromere identity is specified epigenetically by nucleosomes containing the histone H3 variant CENP-A, yet centromeres are almost invariably embedded within repetitive DNA, suggesting that underlying DNA sequences contribute to the organization of centromeric chromatin. In Drosophila melanogaster, CENP-A primarily occupies retroelement-rich islands flanked by simple satellite DNA, but their functional contribution remains unclear. Here, we delete the ~50-kb island Giglio from centromere 3 while preserving the flanking satellites and residual CENP-A chromatin. Despite removal of the DNA sequence associated with most centromeric CENP-A, centromere identity and overall CENP-A levels are preserved at the native locus, indicating that the island itself is not required for centromere identity. Instead, Giglio deletion increases variability in CENP-A chromatin organization, producing highly heterogeneous domain sizes and preferential redistribution of the CENP-A domain into the adjacent dodeca satellite. Together, these findings demonstrate that Giglio is dispensable for centromere identity but constrains the size and position of the CENP-A domain, establishing centromeric islands as key determinants of CENP-A domain architecture.
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BibTeX
@misc{patel2026centromeric,
title = {{Centromeric islands constrain CENP-A domain size and position}},
author = {P. Patel and D. Trasmondi and B. G. Mellone},
howpublished = {bioRxiv},
year = {2026},
month = oct,
doi = {10.64898/2026.10.08.757135},
url = {https://www.biorxiv.org/content/10.64898/2026.10.08.757135v1},
note = {CC BY-NC-ND},
}
RIS
TY - UNPB
TI - Centromeric islands constrain CENP-A domain size and position
AU - P. Patel
AU - D. Trasmondi
AU - B. G. Mellone
PY - 2026
DA - 2026/10/08
PB - bioRxiv
DO - 10.64898/2026.10.08.757135
UR - https://www.biorxiv.org/content/10.64898/2026.10.08.757135v1
AB - Centromere identity is specified epigenetically by nucleosomes containing the histone H3 variant CENP-A, yet centromeres are almost invariably embedded within repetitive DNA, suggesting that underlying DNA sequences contribute to the organization of centromeric chromatin. In Drosophila melanogaster, CENP-A primarily occupies retroelement-rich islands flanked by simple satellite DNA, but their functional contribution remains unclear. Here, we delete the ~50-kb island Giglio from centromere 3 while preserving the flanking satellites and residual CENP-A chromatin. Despite removal of the DNA sequence associated with most centromeric CENP-A, centromere identity and overall CENP-A levels are preserved at the native locus, indicating that the island itself is not required for centromere identity. Instead, Giglio deletion increases variability in CENP-A chromatin organization, producing highly heterogeneous domain sizes and preferential redistribution of the CENP-A domain into the adjacent dodeca satellite. Together, these findings demonstrate that Giglio is dispensable for centromere identity but constrains the size and position of the CENP-A domain, establishing centromeric islands as key determinants of CENP-A domain architecture.
ER -