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Plasmid Fertility inhibition factor
Plasmid fertility inhibition (fin), exemplified by the FinOP system, represses conjugative transfer: FinO protein stabilizes the 79-nt antisense RNA FinP, which blocks traJ mRNA translation; F plasmid finO is IS3-inactivated, so F transfers constitutively.
Plasmid transfer regulator TraJ
TraJ, plasmid transfer regulator of the F sex factor and F-like plasmids in E. coli: primary activator of the 33-kb tra operon from the P_Y promoter, countering H-NS silencing with ArcA, itself repressed by FinOP and Hfq.
PLATZ transcription factor
PLATZ (PLant AT-rich sequence and Zinc-binding) transcription factors are plant-specific zinc-dependent DNA-binding proteins, first found in pea (PLATZ1, 2001), that bind A/T-rich sequences and regulate plant development and salt, drought, and disease stress responses.
Pol I transcription factors (SL1, UBF and RRN3)
Pol I transcription factors SL1, UBF, and RRN3 (TIF-IA) assemble the mammalian RNA polymerase I pre-initiation complex at rDNA promoters, enabling 47S pre-rRNA transcription, Pol I recruitment, promoter escape, and reinitiation.
Poly(A)-binding protein
Poly(A)-binding protein (PABP, PABPC1; nuclear PABPN1) is an RNA-binding protein that binds mRNA poly(A) tails, forming a closed loop with eIF4G/eIF4E to enhance translation, control mRNA decay, and regulate polyadenylation.
Poly(A)-site sequencing
Poly(A)-site sequencing (PAS-seq) is a deep-sequencing method that maps polyadenylation sites across a transcriptome and quantifies RNA abundance, introduced by Peter J. Shepard and colleagues in 2011.
Polyadenylation
Polyadenylation, also called poly(A) tailing, is the non-template addition of adenosines to RNA 3' ends after transcription, producing tails up to 250-300 nucleotides that enable mRNA export, stability, and translation, with alternative polyadenylation affecting over 60% of human genes.
Polycomb recruitment in X chromosome inactivation
Polycomb recruitment in X chromosome inactivation: Xist RNA B-repeat binds hnRNPK, recruiting PCGF3/5-PRC1, whose H2AK119ub recruits PRC2, depositing H3K27me3 on the inactive X.
Polycomb-group proteins
Polycomb-group (PcG) proteins are conserved chromatin regulators, organized into PRC1 and PRC2, that repress HOX and developmental genes via H2AK119ub1 and H3K27me3; deregulation links to cancer.
Polymeric micelles for siRNA delivery
Polymeric micelles for siRNA delivery are nanoscale core-shell carriers of 10 to 100 nm, self-assembled from amphiphilic block copolymers, that protect siRNA and deliver it into cells for gene silencing.
Post-transcriptional modification
Post-transcriptional modification is the chemical and structural alteration of RNA after transcription, including m6A, pseudouridine, m5C, m7G, and A-to-I editing, installed by writer enzymes, removed by erasers, and read by reader proteins to regulate RNA splicing, stability, and translation.
Post-transcriptional regulation
Post-transcriptional regulation controls gene expression on RNA after transcription: capping, splicing, polyadenylation, microRNA repression, and mRNA decay, with kinetic rates and therapeutic applications in RNAi, splice-switching, and mRNA medicines.
Post-transcriptional regulator
Post-transcriptional regulator: an RNA-binding protein or microRNA controlling mRNA turnover, localization, or translation; also InterPro entry IPR025716. Key mechanisms include binding-site competition, sponging, AS-NMD, and alternative polyadenylation.
POU domain
POU domain: conserved ~155-162 amino acid bipartite DNA-binding region of Pit-Oct-Unc transcription factors, with POU-specific and POU-homeodomain subdomains binding the octamer motif ATGCAAAT; key to development and pluripotency.
POU2F2
POU2F2, also known as OCT2 or OTF2, is a human gene on chromosome 19 that encodes a transcription factor controlling immunoglobulin production and B-cell differentiation, and is implicated in lymphoma.
PR-domain zinc finger protein PRDM5-like
PR-domain zinc finger protein PRDM5-like (IPR017125), centered on PRDM5/BCS2/PFM2: a vertebrate-arisen PRDM-family transcriptional repressor with 16 zinc fingers that regulates collagen and ECM genes, is epigenetically silenced in solid tumors, and causes brittle cornea syndrome 2 when mutated.
PRDM16
PRDM16 (PR/SET domain 16), gene at 1p36.32, is a zinc-finger transcription factor controlling brown and beige adipocyte identity, the Myf5-lineage brown fat versus myoblast fate switch, and a therapeutic target in obesity.
Pre-mRNA splicing factor
Pre-mRNA splicing factor (Cwc25/CWC25, CCDC49) is a conserved spliceosomal protein promoting the first branching step of pre-mRNA splicing after Prp2 and Yju2, stabilizing the branch helix until Prp16 removes it.
Precision nuclear run-on sequencing
Precision nuclear run-on sequencing (PRO-seq) is a molecular biology method that maps engaged RNA polymerases genome-wide at base-pair resolution by sequencing the 3' ends of nascent RNA, detecting enhancers and direct transcriptional changes.
Prime editing
Prime editing (PE) is a 2019 CRISPR-derived genome editing method using a Cas9 nickase-reverse transcriptase fusion and pegRNA to install insertions, deletions, and substitutions without double-strand breaks or donor DNA; PE2 through PE7 variants and first clinical uses.
Primer extension
Primer extension is a molecular biology assay in which a labeled DNA primer is extended on an RNA template to map a transcript's 5′ start site or genotype a variant.
pRNA nanoparticles
pRNA nanoparticles are nanostructures built from packaging RNA of the bacteriophage phi29 DNA packaging motor, engineered to deliver siRNA and other therapeutics to targeted cells.
Processing snoRNAs
Processing snoRNAs are small nucleolar RNAs, including U3, U8, U14, and U17/snR30, that guide cleavage of precursor ribosomal RNA instead of guiding chemical modification of rRNA nucleotides.
PROCT domain
PROCT domain (IPR012984), also NUC072, Pfam PF08084: the C-terminal conserved domain of Prp8 pre-mRNA splicing factors, detected alongside PRO8NT and snRNA-binding domains in eukaryotic spliceosomal proteins.
Progesterone receptor
Progesterone receptor (PR, PGR gene): nuclear steroid receptor with PR-A and PR-B isoforms mediating progesterone action in uterus and breast; clinical biomarker for endocrine therapy response.
Promoter escape and early transcriptional pausing
Promoter escape is the step in which RNA polymerase II leaves the promoter and its general transcription factors, followed by an early pausing stop before productive elongation.
Protein male-specific lethal-1
Protein male-specific lethal-1 (MSL1), Drosophila scaffold of the MSL dosage compensation complex; dimerizes, binds MSL2, MSL3, MOF, targets the male X chromosome; loss causes male-specific lethality.
Protein SUPPRESSOR OF GENE SILENCING 3
SGS3 (SUPPRESSOR OF GENE SILENCING 3, At5g23570) is a plant-specific RNA-binding protein that, with RDR6 in siRNA bodies, enables secondary siRNA and tasiRNA biogenesis, leaf development, and antiviral silencing, and is targeted by viral suppressors such as V2, p20, and AC4.
Protospacer adjacent motif
The protospacer adjacent motif (PAM) is a short DNA sequence, usually 2–5 nucleotides long, next to a CRISPR target that most CRISPR-Cas systems require for spacer acquisition and cleavage.
Proximity ligation-assisted ChIP-seq
Proximity ligation-assisted ChIP-seq (PLAC-seq) is a chromatin conformation capture method, introduced in 2016, that maps long-range DNA interactions anchored at regions bound by a protein of interest.