TY  - JOUR
AU  - Fatmaoui, Fadwa
AU  - Carrivain, Pascal
AU  - Taiki, Fatima
AU  - Iusupova, Amina
AU  - Grewe, Diana
AU  - Hagen, Wim
AU  - Jakob, Burkhard
AU  - Victor, Jean-Marc
AU  - Leforestier, Amélie
AU  - Eltsov, Mikhail
TI  - Direct visualization and tracing of chromatin folding in the Drosophila embryo.
JO  - The EMBO journal
VL  - 45
IS  - 5
SN  - 0261-4189
CY  - [London]
PB  - Nature Publishing Group UK
M1  - GSI-2026-00570
SP  - 1621 - 1647
PY  - 2026
AB  - Chromatin organization, through the assembly of DNA with histones and the folding of nucleosome chains, regulates DNA accessibility for transcription, DNA replication and repair. Although models derived from in vitro studies have proposed distinct nucleosome chain geometries, the organization of chromatin within the crowded cell nucleus remains elusive. Using cryo-electron tomography of thin vitreous sections, we directly observed the path of nucleosomal and linker DNA in situ from a flash-frozen organism - Drosophila embryos. We quantified linker length and curvature, characterizing an irregular zig-zag chromatin-folding motif, with a low degree of linker bending. Nucleosome conformations could be identified on individual particles in favorable orientations without structure averaging. Additionally, we observed particles that accommodate a number of DNA gyres ranging from less than one to up to three, which resemble previously proposed non-octameric nucleosomal particles with variable DNA wrapping.
KW  - Animals
KW  - Nucleosomes: ultrastructure
KW  - Nucleosomes: metabolism
KW  - Chromatin: ultrastructure
KW  - Chromatin: metabolism
KW  - Chromatin: chemistry
KW  - Embryo, Nonmammalian: ultrastructure
KW  - Embryo, Nonmammalian: metabolism
KW  - Drosophila melanogaster: embryology
KW  - DNA: metabolism
KW  - DNA: chemistry
KW  - DNA: ultrastructure
KW  - Cryoelectron Microscopy
KW  - Electron Microscope Tomography
KW  - Drosophila: embryology
KW  - Chromatin Fiber (Other)
KW  - In Situ Cryo-Electron Tomography (Other)
KW  - Linker DNA (Other)
KW  - Nucleosome (Other)
KW  - Sub-Nucleosomal Particles (Other)
KW  - Nucleosomes (NLM Chemicals)
KW  - Chromatin (NLM Chemicals)
KW  - DNA (NLM Chemicals)
LB  - PUB:(DE-HGF)16
C6  - pmid:41663843
C2  - pmc:PMC12954082
DO  - DOI:10.1038/s44318-026-00701-7
UR  - https://repository.gsi.de/record/366781
ER  -