Available structures
PDBOrtholog search: PDBe RCSB
Aliases PTBP1, HNRNP-I, HNRNPI, HNRPI, PTB, PTB-1, PTB-T, PTB2, PTB3, PTB4, pPTB, polypyrimidine tract binding protein 1
External IDs MGI: 97791 HomoloGene: 49188 GeneCards: PTBP1
RNA expression pattern

More reference expression data
Species Human Mouse









RefSeq (mRNA)



RefSeq (protein)



Location (UCSC) Chr 19: 0.8 – 0.81 Mb Chr 10: 79.85 – 79.86 Mb
PubMed search [1] [2]
View/Edit HumanView/Edit Mouse

Polypyrimidine tract-binding protein 1 is a protein that in humans is encoded by the PTBP1 gene.[3][4][5]

This gene belongs to the subfamily of ubiquitously expressed heterogeneous nuclear ribonucleoproteins (hnRNPs). The hnRNPs are RNA-binding proteins and they complex with heterogeneous nuclear RNA (hnRNA). These proteins are associated with pre-mRNAs in the nucleus and appear to influence pre-mRNA processing and other aspects of mRNA metabolism and transport. While all of the hnRNPs are present in the nucleus, some seem to shuttle between the nucleus and the cytoplasm. The hnRNP proteins have distinct nucleic acid binding properties. The protein encoded by this gene has four repeats of quasi-RNA recognition motif (RRM) domains that bind RNAs. This protein binds to the intronic polypyrimidine tracts that requires pre-mRNA splicing and acts via the protein degradation ubiquitin-proteasome pathway. It may also promote the binding of U2 snRNP to pre-mRNAs. This protein is localized in the nucleoplasm and it is also detected in the perinucleolar structure. Alternatively spliced transcript variants encoding different isoforms have been described.[5]

PTBP1 In Mammals

In brains of mammals, transcripts from the PTBP1 gene are missing one exon (exon 9) that is included in the brains of other vertebrates, as a result of alternative splicing. This contributes to the evolutionary difference between the nervous system of mammals and other vertebrates.[6]


PTBP1 has been shown to interact with HNRPK,[7] PCBP2,[7] SFPQ[8][9] and HNRNPL.[7][10]

This gene is targeted by the microRNA miR-124. During neuronal differentiation, miR-124 reduces PTBP1 levels, leading to the accumulation of correctly spliced PTBP2 mRNA and a dramatic increase in PTBP2 protein.[11]


  1. "Human PubMed Reference:".
  2. "Mouse PubMed Reference:".
  3. Patton JG, Mayer SA, Tempst P, Nadal-Ginard B (August 1991). "Characterization and molecular cloning of polypyrimidine tract-binding protein: a component of a complex necessary for pre-mRNA splicing". Genes Dev. 5 (7): 1237–51. doi:10.1101/gad.5.7.1237. PMID 1906036.
  4. Romanelli MG, Lorenzi P, Morandi C (November 2000). "Organization of the human gene encoding heterogeneous nuclear ribonucleoprotein type I (hnRNP I) and characterization of hnRNP I related pseudogene". Gene. 255 (2): 267–72. doi:10.1016/S0378-1119(00)00331-0. PMID 11024286.
  5. 1 2 "Entrez Gene: PTBP1 polypyrimidine tract binding protein 1".
  6. Gueroussov, Serge; Gonatopoulos-Pournatzis, Thomas; Irimia, Manuel; Raj, Bushra; Lin, Zhen-Yuan; Gingras, Anne-Claude; Blencowe, Benjamin J. (August 2015). "An alternative splicing event amplifies evolutionary differences between vertebrates". Science. 349 (6250): 868–873. doi:10.1126/science.aaa8381.
  7. 1 2 3 Kim, J H; Hahm B; Kim Y K; Choi M; Jang S K (May 2000). "Protein-protein interaction among hnRNPs shuttling between nucleus and cytoplasm". J. Mol. Biol. ENGLAND. 298 (3): 395–405. doi:10.1006/jmbi.2000.3687. ISSN 0022-2836. PMID 10772858.
  8. Patton, J G; Porro E B; Galceran J; Tempst P; Nadal-Ginard B (March 1993). "Cloning and characterization of PSF, a novel pre-mRNA splicing factor". Genes Dev. UNITED STATES. 7 (3): 393–406. doi:10.1101/gad.7.3.393. ISSN 0890-9369. PMID 8449401.
  9. Meissner, M; Dechat T; Gerner C; Grimm R; Foisner R; Sauermann G (January 2000). "Differential nuclear localization and nuclear matrix association of the splicing factors PSF and PTB". J. Cell. Biochem. UNITED STATES. 76 (4): 559–66. doi:10.1002/(SICI)1097-4644(20000315)76:4<559::AID-JCB4>3.0.CO;2-U. ISSN 0730-2312. PMID 10653975.
  10. Hahm, B; Cho O H; Kim J E; Kim Y K; Kim J H; Oh Y L; Jang S K (April 1998). "Polypyrimidine tract-binding protein interacts with HnRNP L". FEBS Lett. NETHERLANDS. 425 (3): 401–6. doi:10.1016/S0014-5793(98)00269-5. ISSN 0014-5793. PMID 9563502.
  11. Makeyev EV, Zhang J, Carrasco MA, Maniatis T (August 2007). "The MicroRNA miR-124 Promotes Neuronal Differentiation by Triggering Brain-Specific Alternative Pre-mRNA Splicing". Mol. Cell. 27 (3): 435–48. doi:10.1016/j.molcel.2007.07.015. PMC 3139456Freely accessible. PMID 17679093.

Further reading

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