Insulators As Dynamic, Tunable Regulators of Enhancer-Promoter Coordination in Living Drosophila Embryos
- 1University of Pennsylvania
Abstract
The three-dimensional organization of the genome enables enhancers and promoters to interact across vast distances and direct transcription. Yet whether architectural elements, such as insulators, serve as rigid, passive barriers or as dynamic, active organizers of this communication remains unclear. Here, using single-cell, live imaging of a Drosophila transgene in which a single enhancer regulates two equidistant promoters, we confirm that the enhancer engages both promoters simultaneously and show that coordinated bursting is intrinsically more productive than uncoordinated activity. Flanking this system with insulators increases coordinated bursting frequency and transcriptional output, indicating that insulator-mediated looping promotes multi-way enhancer-promoter interaction. Further, bidirectionally-paired, homotypic insulators produce stronger coordination than unidirectional pairs. Inserting an intermediate insulator to generate competing loop configurations, together with two-state promoter modeling, we show that these chromatin loops are highly dynamic. This work reframes insulators as active, tunable regulators that shape the frequency, coordination, and productivity of enhancer-promoter communication.
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BibTeX
@misc{buitrago2026insulators,
title = {{Insulators As Dynamic, Tunable Regulators of Enhancer-Promoter Coordination in Living Drosophila Embryos}},
author = {N. Buitrago and C. Nieto and A. Singh and B. Lim},
howpublished = {bioRxiv},
year = {2026},
month = sep,
doi = {10.64898/2026.09.09.750400},
url = {https://www.biorxiv.org/content/10.64898/2026.09.09.750400v1},
note = {CC BY-NC-ND},
}
RIS
TY - UNPB
TI - Insulators As Dynamic, Tunable Regulators of Enhancer-Promoter Coordination in Living Drosophila Embryos
AU - N. Buitrago
AU - C. Nieto
AU - A. Singh
AU - B. Lim
PY - 2026
DA - 2026/09/09
PB - bioRxiv
DO - 10.64898/2026.09.09.750400
UR - https://www.biorxiv.org/content/10.64898/2026.09.09.750400v1
AB - The three-dimensional organization of the genome enables enhancers and promoters to interact across vast distances and direct transcription. Yet whether architectural elements, such as insulators, serve as rigid, passive barriers or as dynamic, active organizers of this communication remains unclear. Here, using single-cell, live imaging of a Drosophila transgene in which a single enhancer regulates two equidistant promoters, we confirm that the enhancer engages both promoters simultaneously and show that coordinated bursting is intrinsically more productive than uncoordinated activity. Flanking this system with insulators increases coordinated bursting frequency and transcriptional output, indicating that insulator-mediated looping promotes multi-way enhancer-promoter interaction. Further, bidirectionally-paired, homotypic insulators produce stronger coordination than unidirectional pairs. Inserting an intermediate insulator to generate competing loop configurations, together with two-state promoter modeling, we show that these chromatin loops are highly dynamic. This work reframes insulators as active, tunable regulators that shape the frequency, coordination, and productivity of enhancer-promoter communication.
ER -