nuclear net

cellstructuremech:nuclear_net · Membrane organelle · Membrane · Proposed

A reticulating double-membrane network characterized inside the nucleus of the dinoflagellate Polykrikos kofoidii. Its strands interconnect dinomitotic tunnels and the peripheral nuclear envelope, with regularly spaced swellings along the inner strands; the network is continuous with and forms part of the nuclear envelope. [DOI:10.1038/s41598-018-37065-w]

Polykrikos kofoidii, Figure 3. A-C: FIB-SEM sections showing strands and membranous swellings between the nuclear envelope and a tunnel. D-F: reconstructed net in red over section images; surrounding anatomy is shown for context. G: the six numbered tunnels and connecting strands in this reconstruction. This is the observed count in one specimen, not a universal count. SEM · *Polykrikos kofoidii* (`NCBITaxon:271679`) · Gregory S. Gavelis, Maria Herranz, Kevin C. Wakeman, Christina Ripken, Satoshi Mitarai, Gillian H. Gile, Patrick J. Keeling, Brian S. Leander; CC BY, via PubMed Central · CC_BY_4_0 · source: PMC PMC6351617.1 Fig3 · `DOI:10.1038/s41598-018-37065-w`

Part of: nuclear envelope (GO:0005635)

UniProt location names: UniProt Consortium, CC BY 4.0. Reference label and route sources.

Components

Component	Type	Part of / acts on	Grounding	Genes	Stoichiometry	Essential	Role
membrane	Other	part of	`GO:0016020`			UNKNOWN	Two membranes line the strands and continue into those lining the dinomitotic tunnels. `DOI:10.1038/s41598-018-37065-w` Results describe double-membrane strands; no molecular inventory or assembly-essentiality test is reported.

Canonical examples

NCBITaxon:271679 Polykrikos kofoidii — Wild-collected pseudocolonies. One specimen was reconstructed by FIB-SEM after high-pressure freezing and freeze substitution, complemented by TEM and confocal observations of additional specimens. [DOI:10.1038/s41598-018-37065-w]

Discussions

CURATION_TODO (RESOLVED): Distinguish the nuclear net from broader nuclear-envelope invaginations and neighboring structures. An exact mapping must denote the same entity rather than import unverified features.
CURATION_TODO (RESOLVED): Do not promote immunofluorescence proximity into a molecular constituent assignment. Confocal correspondence alone does not resolve the molecular composition of individual membrane strands.
CURATION_TODO (OPEN): Establish molecular machinery, function, cell-cycle dynamics and three-dimensional occurrence beyond Polykrikos kofoidii. A reconstructed static network does not establish transport, mitotic force generation or clade-wide prevalence.

Evidence

DOI:10.1038/s41598-018-37065-w Gavelis et al. (2019), Scientific Reports. Primary Results, Discussion, Conclusion, Methods and Figure 3 read via publisher and PMC BioC/JATS. Three-dimensional continuity supports nuclear-envelope parthood; chemical fixation disrupts the finer network. Neither lumenal flow nor a division mechanism was demonstrated.
GO:0005622 Verified broad intracellular-anatomical-structure parent. This named membrane network is not asserted to be a separate sealed organelle or the entire nuclear envelope.

Curation history

2026-10-03T17:14:01Z codex · CREATED_RECORD — Scaffolded by scripts/new_record.py
2026-10-03T17:15:43Z codex · EXPANDED_RECORD — Added verified nuclear-envelope topology, membrane constituent class, Polykrikos microscopy example, ontology and molecular evidence boundaries, unresolved functional scope and inspected CC BY Figure 3.

Source: data/structures/membrane_organelle/nuclear_net.yaml