Multi-foci replication domains in Haloferax volcanii visualised by super-resolution microscopy
Abstract
The archaeon Haloferax volcanii is a unique model organism to investigate replication dynamics and dissect the interplay between multiple origins, alternative replication pathways, and polyploidy. The combination of variable chromosome copy number and asynchronous replication across the cell population gives rise to pronounced phenotypic heterogeneity, further increasing system complexity. To investigate these mechanisms, we implemented (spt-)PALM and STORM microscopy to probe replication dynamics in different cell lines and growth conditions. We established the first STORM-based superresolution imaging approach of a protein in Haloferax volcanii. Altogether, our results support a model in which each H. volcanii cell replicates a constant fraction of its chromosome copies, irrespective of total ploidy. Consequently, cells with a higher number of chromosomes exhibit proportionally more replication forks, resulting in pronounced ploidy heterogeneity across the population. Moreover, we show that replication foci are not randomly distributed but cluster into discrete Replication Domains containing multiple active sites. This organization persists across different growth conditions and is independent of canonical replication origins, as demonstrated in a strain lacking all four origins. Our findings suggest that replication coordination in H. volcanii is governed by spatial architecture rather than origin-dependent initiation, providing new insights into the evolutionary diversity of replication control mechanisms.
.
Related
- High-resolution single-molecule replication profiling of the human genome
- High-resolution microscopy of whole plant cells reveals virus-induced changes to intercellular connectivity
- Diffusion MR Microscopy of the Human Hippocampus at 50 μm Resolution at 14.1 T for 3D Virtual Histology
- Adaptation of Iterative Ultrastructure Expansion Microscopy (iU-ExM) enables high-resolution imaging of the cytoskeleton and subcellular architecture of Trypanosoma cruzi
- Comparative genomics and super-resolution microscopy of novel cyanophages reveals genomic isomerism, auxiliary genes, and a non-synchronous infection process
BibTeX
@misc{noury2026multifoci,
title = {{Multi-foci replication domains in Haloferax volcanii visualised by super-resolution microscopy}},
author = {Dorian Noury and Titouan D’yvoire and Ulrike Endesfelder and Stephane Duigou and Nicolas Olivier and Roxane Lestini},
howpublished = {HAL},
year = {2026},
month = sep,
doi = {10.64898/2026.09.02.748831},
url = {https://cnrs.hal.science/hal-05830150v1},
note = {CC BY-NC 4.0},
}
RIS
TY - UNPB
TI - Multi-foci replication domains in Haloferax volcanii visualised by super-resolution microscopy
AU - Dorian Noury
AU - Titouan D’yvoire
AU - Ulrike Endesfelder
AU - Stephane Duigou
AU - Nicolas Olivier
AU - Roxane Lestini
PY - 2026
DA - 2026/09/02
PB - HAL
DO - 10.64898/2026.09.02.748831
UR - https://cnrs.hal.science/hal-05830150v1
AB - The archaeon Haloferax volcanii is a unique model organism to investigate replication dynamics and dissect the interplay between multiple origins, alternative replication pathways, and polyploidy. The combination of variable chromosome copy number and asynchronous replication across the cell population gives rise to pronounced phenotypic heterogeneity, further increasing system complexity. To investigate these mechanisms, we implemented (spt-)PALM and STORM microscopy to probe replication dynamics in different cell lines and growth conditions. We established the first STORM-based superresolution imaging approach of a protein in Haloferax volcanii. Altogether, our results support a model in which each H. volcanii cell replicates a constant fraction of its chromosome copies, irrespective of total ploidy. Consequently, cells with a higher number of chromosomes exhibit proportionally more replication forks, resulting in pronounced ploidy heterogeneity across the population. Moreover, we show that replication foci are not randomly distributed but cluster into discrete Replication Domains containing multiple active sites. This organization persists across different growth conditions and is independent of canonical replication origins, as demonstrated in a strain lacking all four origins. Our findings suggest that replication coordination in H. volcanii is governed by spatial architecture rather than origin-dependent initiation, providing new insights into the evolutionary diversity of replication control mechanisms. .
ER -