1,440 articles
Nocodazole
Nocodazole is a synthetic benzimidazole compound that binds tubulin at the colchicine site and depolymerizes microtubules, widely used to arrest cells in mitosis in laboratory research.
Nodulin
Nodulin, especially nodulin 26 (NOD26), is a 26.5 kDa soybean symbiosome membrane aquaporin and archetype of the plant NIP aquaglyceroporin family, transporting water, glycerol, formamide, and ammonia in legume-rhizobia nitrogen-fixing nodules.
Nonhomologous End-Joining (NHEJ)
Nonhomologous end-joining (NHEJ), also called classical or canonical NHEJ, is the Ku-dependent DNA double-strand break repair pathway that directly reseals broken DNA ends without a homologous template; it operates throughout the cell cycle, is essential for V(D)J recombination, and has a Ku-independent backup, alternative end joining (MMEJ).
Nonlinear optical microscopy
Nonlinear optical microscopy is a family of imaging techniques that use nonlinear light–matter interactions, such as multiphoton absorption and harmonic generation, to image live tissue.
NPC1L1
NPC1L1 (Niemann-Pick C1-like 1) is an intestinal membrane protein that transports cholesterol and plant sterols into enterocytes and is the molecular target of the cholesterol-lowering drug ezetimibe; knockout mice lose over 70% of cholesterol absorption.
Nuclear bodies
Nuclear bodies are membraneless, phase-separated compartments in the cell nucleus, including the nucleolus, Cajal bodies, nuclear speckles, paraspeckles, and PML bodies, which concentrate proteins and RNAs for RNA processing, assembly, and gene regulation.
Nuclear envelope
Nuclear envelope (NE): double membrane (inner and outer nuclear membranes, perinuclear space) enclosing the eukaryotic nucleus, perforated by ~120 nm nuclear pore complexes and lined by the lamin nuclear lamina; handles transport, mechanotransduction, open mitosis disassembly, and laminopathies.
Nuclear Envelope Breakdown
Nuclear envelope breakdown (NEBD): disassembly of the nuclear envelope in late prophase of open mitosis, via nuclear pore disassembly, lamin depolymerization, and membrane clearance, driven by CDK1 and other mitotic kinases.
Nuclear localization sequence
Nuclear localization sequence (NLS): short basic amino acid motif, e.g. SV40 large T PKKKRKV, that directs proteins into the nucleus via importin-mediated nuclear pore transport; classical monopartite and bipartite types plus PY-NLS exist.
Nuclear pore complex
Nuclear pore complex (NPC): ~110-MDa, ~1,000-protein channel of 30 nucleoporins spanning the nuclear envelope, mediating selective FG-repeat-gated nucleocytoplasmic transport, gene regulation, and disease-linked dysfunction.
Nuclear pore complex protein
Nuclear pore complex components, or nucleoporins (Nups), are the ~30 proteins, about 600 copies each, that build the NPC gateway in the nuclear envelope; FG-nups form the transport barrier, and NUP mutations cause leukemia, triple A syndrome, and ALS.
Nucleate cell
Nucleate cell (CL:0002242), Cell Ontology class defined as a cell containing at least one nucleus; parent of single and multinucleate cell, leukocyte, and nucleate erythrocyte.
Nucleated red blood cell
Nucleated red blood cell (NRBC, normoblast, erythroblast): immature red cell precursor retaining a nucleus; absent from adult peripheral blood, normal in newborns, and counted by automated hematology analyzers.
Nucleoid
Nucleoid: the membrane-free region of bacterial and archaeal cells holding the condensed chromosome with proteins and RNA. Key facts: 80/10/10 DNA/protein/RNA in E. coli, ~1000-fold compaction, six macrodomains, NAPs like HU and H-NS.
Nucleolar and spindle-associated protein 1
NUSAP1 (NuSAP), nucleolar and spindle-associated protein 1, is a 55 kDa microtubule- and chromatin-binding protein regulating mitotic spindle assembly, RanGTP/importin controlled, overexpressed in many cancers as a prognostic biomarker.
Nucleolus
Nucleolus: largest membraneless organelle in the eukaryotic nucleus, site of ribosome biogenesis. Forms around rDNA NORs on acrocentric chromosomes via liquid-liquid phase separation; also regulates stress response, aging, and cancer.
Nucleolus organizer region
Nucleolus organizer region (NOR), also called nucleolar organizing region: chromosomal locus of tandem ribosomal DNA repeats that seeds the nucleolus; in humans on acrocentric chromosomes 13, 14, 15, 21, 22, detected by AgNOR silver staining.
Obsolete CP:0000040
Obsolete CP:0000040 is a deprecated Cell Ontology class identifier using the non-standard CP prefix, proposed for obsoletion in GitHub issue #572 and replaced by the CL identifier for monoblast (CL:0000040).
Occludin
Occludin (OCLN, UniProt Q16625) is a ~65 kDa four-transmembrane protein at tight junctions, first identified in 1993 from chicken liver; it binds ZO-1, regulates barrier permeability, and links to Pseudo-TORCH syndrome.
Odontoblast
Odontoblast: dentin-forming cell lining the tooth pulp cavity, derived from neural crest mesenchyme; induced by inner enamel epithelium, secretes predentin, forms sclerotic and reparative dentin, and acts in pulp sensory defense.
OE19
OE19 (OE-19, JROECL19, CVCL_1622) is a human esophageal adenocarcinoma cell line established in 1993 from a 72-year-old man, HER2/ERBB2-amplified, lapatinib-sensitive, microsatellite stable, and distributed by ECACC and DSMZ.
Oenocyte
Oenocyte (oenocytes): large secretory cells of ectodermal origin in arthropods, mainly insects, specialized in very-long-chain fatty acid and cuticular hydrocarbon synthesis; hepatocyte-like, linked to fat body and tracheae; Cell Ontology CL:0000487.
Olfactory epithelium
Olfactory epithelium (OE), the sensory neuroepithelium of the nasal cavity containing olfactory receptor neurons, sustentacular cells, and regenerative basal cells; detects odorants via one-receptor-per-neuron cilia and renews neurons every 30–90 days.
Oliver Daumke
Oliver Daumke is a German structural biologist and senior group leader at the Max Delbrück Center in Berlin, known for crystal structures of the membrane-scission GTPase dynamin and of Mgm1.
Oncocyte
An oncocyte, also called an oxyphil cell or, in the thyroid, a Hürthle cell, is an enlarged epithelial cell with granular pink cytoplasm caused by accumulated mitochondria.
Oncogene Induced Senescence
Oncogene-induced senescence (OIS) is a permanent proliferative arrest triggered by oncogene activation (RAS, BRAF, AKT) or tumor suppressor loss (RB1, PTEN), mediated by p16-RB and p14ARF-p53 pathways, acting as a tumor-suppressive barrier with SASP-mediated double-edged effects.
Onda 11
Onda 11 (Onda-11, no.11, CVCL_3076) is a human glioblastoma cell line from the right parietal lobe of a 64-year-old Japanese woman, GFAP-positive, PTEN and TP53 mutant, with the strongest ADD3 dependency among DepMap GBM lines.
Opalin
Opalin (TMEM10, OPALIN gene) is a mammalian-specific CNS myelin protein: a 141-aa type I transmembrane sialylglycoprotein of oligodendrocyte paranodal loops that promotes oligodendrocyte differentiation and acts as the LGI1 receptor.
Optical pooled screening
Optical pooled screening is a cell-biology method that applies pooled perturbations to a mixed cell population, images each cell's phenotype, and identifies each cell's perturbation in place.
Optogenetic stimulation
Optogenetic stimulation uses genetically expressed, light-activated proteins, typically channelrhodopsins, to control the electrical activity of specified cells in living tissue with millisecond precision, first demonstrated by Edward S. Boyden and colleagues in 2005.