RNA and gene regulation

NCOA1

NCOA1 (SRC-1, RIP160, KAT13A) is the first-cloned nuclear receptor coactivator, a ~160-kDa p160-family protein with intrinsic histone acetyltransferase activity that coactivates steroid and nuclear hormone receptors; dysregulation links to breast and esophageal cancer and inherited obesity.

NEAT1

NEAT1 (nuclear paraspeckle assembly transcript 1, MEN-ε/β, VINC-1) is a mammalian long noncoding RNA with 3.7-kb and 23-kb isoforms on chromosome 11 that scaffolds paraspeckle nuclear bodies regulating gene sequestration, stress responses, and cancer.

NF-kappa-B-activating protein

NF-kappa-B-activating protein (NKAP, Q8N5F7) is a 415-aa human X-linked nuclear protein acting as an HDAC3/Notch transcriptional corepressor required for T-cell development, RNA splicing, and R-loop suppression; paralog NKAPL is testis-specific.

NF-κB

NF-κB (nuclear factor kappa-light-chain-enhancer of activated B cells) is a transcription factor family discovered by Sen and Baltimore in 1986, regulating immunity and inflammation via canonical (IKKβ/IκBα) and non-canonical (NIK/IKKα/p100) pathways, and implicated in cancer and inflammatory disease.

Nitrogen regulatory AreA, N-terminal

Nitrogen regulatory AreA, N-terminal (InterPro IPR011420) is the N-terminal protein domain of AreA, the GATA transcription factor mediating nitrogen metabolite repression in Aspergillus fungi; the region is variable and dispensable for DNA binding but affects derepression.

No-go decay

No-go decay (NGD) is a eukaryotic mRNA surveillance pathway, defined by Doma and Parker in 2006, that resolves ribosomes stalled on problematic mRNA sequences and degrades the stalled message.

NOMe-seq

NOMe-seq (nucleosome occupancy and methylome sequencing) is a bench biology method, introduced in 2012, that measures nucleosome positioning and DNA methylation on the same DNA molecule.

Non-coding RNA

Non-coding RNA (ncRNA): RNA transcribed from DNA but not translated into protein, spanning rRNA, tRNA, miRNA, siRNA, piRNA, and lncRNA classes; roughly 98% of the human transcriptome, central to gene regulation, genome-function debates, and RNA therapeutics.

Non-stop decay

Non-stop decay (NSD, nonstop mRNA decay): eukaryotic surveillance pathway degrading mRNAs lacking stop codons; stalled ribosomes at the 3' end recruit Ski7/Hbs1-Dom34 and the exosome for 3'-to-5' degradation.

Noncanonical and moonlighting functions of aminoacyl-tRNA synthetases

Several aminoacyl-tRNA synthetases (aaRSs) carry out moonlighting, non-translational jobs as cytokines, transcriptional regulators, signaling components, and structural scaffolds, often activated by proteolysis, alternative splicing, or alternative polyadenylation.

Nonsense-mediated decay

Nonsense-mediated decay (NMD), or nonsense-mediated mRNA decay, is a conserved eukaryotic RNA surveillance pathway that degrades mRNAs with premature termination codons via UPF1, SMG proteins, and exon-junction complexes, also regulating normal gene expression.

Northern blot

The Northern blot is a molecular biology technique that separates RNA by gel electrophoresis and detects a chosen sequence with a labeled probe, reporting a transcript's size and abundance.

NOVA proteins

NOVA proteins, short for neuro-oncological ventral antigens, are the neuron-specific RNA-binding proteins NOVA1 and NOVA2, first identified in 1993 as targets of the Ri antibody in paraneoplastic opsoclonus-ataxia.

NR4A2

NR4A2 (NURR1, NOT, TINUR, RNR1, HZF-3) is a human orphan nuclear receptor transcription factor on chromosome 2, an immediate early gene essential for dopaminergic neuron development and implicated in Parkinson's disease, schizophrenia, and neurodevelopmental disorder.

Nuclear abundant poly(A) RNA-binding protein Nab2, N-terminal

N-terminal domain of yeast Nab2 (Nab2-N, residues 1-97), a PWI-like five-helix protein-interaction module that binds Mlp1 via Phe73 and Gfd1 via Tyr34 to drive mRNA nuclear export; binds no nucleic acid.

Nuclear export signal

Nuclear export signal (NES), also leucine-rich NES: short hydrophobic peptide motif (8-15 residues, 3-5 hydrophobic positions) in proteins such as HIV-1 Rev and PKI that directs nuclear export by binding the exportin CRM1/XPO1 with RanGTP.

Oct 20, 2026

Nuclear Factor Erythroid-derived 2-like

Nuclear factor erythroid-derived 2-like (NFE2L, also called NF-E2-related factor or Nrf) is a family of bZIP transcription factors that regulate stress-responsive gene expression in animals.

Nuclear factor of activated T cells (NFAT)

NFAT (nuclear factor of activated T cells), also NF-AT or NFATC proteins, is a five-member transcription factor family (NFATc1-c4, NFAT5/TonEBP) activated by calcium-calmodulin-calcineurin signaling, targeted by cyclosporin A and FK506, and involved in immunity, development, cancer, and autoimmunity.

Oct 20, 2026

Nuclear hormone receptor, ligand-binding domain

Nuclear hormone receptor ligand-binding domain (LBD), region E of nuclear receptors; C-terminal ~250-residue 12-helix sandwich with hydrophobic ligand-binding pocket and AF-2 helix 12 charge clamp for coactivator recruitment; main drug discovery target.

Nuclear receptor

Nuclear receptors (NRs) are ligand-activated transcription factors, 48 in humans, that bind steroids, thyroid hormone, vitamin D, retinoic acid, and fatty acids, bind DNA at hormone response elements, and are targets for 15–20% of drugs.

Nuclear receptor coactivator

Nuclear receptor coactivator: a protein that binds hormone-activated nuclear receptors via LXXLL motifs and boosts target-gene transcription; first member SRC-1, p160 SRC family of three, over 400 coregulators known.

Nuclear receptor corepressor

Nuclear receptor corepressor, also known as NCoR or NCOR1, is a large transcriptional corepressor protein, cloned in 1995, that binds unliganded nuclear receptors and represses target genes by recruiting HDAC3-containing complexes.

Nuclear run-on assay

The nuclear run-on assay is a molecular biology technique measuring active gene transcription by letting isolated nuclei extend initiated transcripts with labeled nucleotides, independent of RNA stability.

Nuclear segregation protein Bfr1

Nuclear segregation protein Bfr1 (Bfr1p, BFR1/YOR198C) is a 55 kDa RNA-binding protein of Saccharomyces cerevisiae, found as a brefeldin A resistance suppressor, that binds polyribosome mRNPs with Scp160p and regulates ER-local translation.

Nuclease protection assay

The nuclease protection assay (NPA) is a molecular biology method that quantifies and maps specific RNA or DNA using a labeled antisense probe and nuclease digestion.

Nucleoside-modified mRNA

Nucleoside-modified mRNA is synthetic messenger RNA in which natural bases are replaced with analogs such as pseudouridine, established by Karikó and Weissman in 2005 and recognized with the 2023 Nobel Prize.

Nucleosome assembly

Nucleosome assembly deposits H3-H4 tetramers and H2A-H2B dimers onto DNA via histone chaperones: CAF-1 with PCNA in replication-coupled assembly of H3.1, and HIRA or DAXX in replication-independent assembly of H3.3, with ASF1 as the central handoff chaperone.