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RefSeq (mRNA)



RefSeq (protein)



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Heterogeneous nuclear ribonucleoprotein U is a protein that in humans is encoded by the HNRNPU gene.[1][2]


This gene belongs to the subfamily of ubiquitously expressed heterogeneous nuclear ribonucleoproteins (hnRNPs). The hnRNPs are RNA binding proteins that form complexes 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 contains a RNA binding domain and scaffold-associated region (SAR)-specific bipartite DNA-binding domain. This protein is also thought to be involved in the packaging of hnRNA into large ribonucleoprotein complexes. During apoptosis, this protein is cleaved in a caspase-dependent way. Cleavage occurs at the SALD site, resulting in a loss of DNA-binding activity and a concomitant detachment of this protein from nuclear structural sites. But this cleavage does not affect the function of the encoded protein in RNA metabolism. At least two alternatively spliced transcript variants have been identified for this gene.[3]


HNRPU has been shown to interact with:


  1. Fackelmayer FO, Richter A (Mar 1994). "hnRNP-U/SAF-A is encoded by two differentially polyadenylated mRNAs in human cells". Biochim Biophys Acta. 1217 (2): 232–4. doi:10.1016/0167-4781(94)90044-2. PMID 7509195.
  2. Fackelmayer FO, Richter A (Sep 1994). "Purification of two isoforms of hnRNP-U and characterization of their nucleic acid binding activity". Biochemistry. 33 (34): 10416–22. doi:10.1021/bi00200a024. PMID 8068679.
  3. "Entrez Gene: HNRNPU heterogeneous nuclear ribonucleoprotein U (scaffold attachment factor A)".
  4. Martens JH, Verlaan M, Kalkhoven E, Dorsman JC, Zantema A (Apr 2002). "Scaffold/matrix attachment region elements interact with a p300-scaffold attachment factor A complex and are bound by acetylated nucleosomes". Mol. Cell. Biol. 22 (8): 2598–606. doi:10.1128/mcb.22.8.2598-2606.2002. PMC 133732. PMID 11909954.
  5. Kim MK, Nikodem VM (Oct 1999). "hnRNP U inhibits carboxy-terminal domain phosphorylation by TFIIH and represses RNA polymerase II elongation". Mol. Cell. Biol. 19 (10): 6833–44. PMC 84680. PMID 10490622.
  6. Eggert M, Michel J, Schneider S, Bornfleth H, Baniahmad A, Fackelmayer FO, Schmidt S, Renkawitz R (Nov 1997). "The glucocorticoid receptor is associated with the RNA-binding nuclear matrix protein hnRNP U". J. Biol. Chem. 272 (45): 28471–8. doi:10.1074/jbc.272.45.28471. PMID 9353307.
  7. Taniura H, Yoshikawa K (2002). "Necdin interacts with the ribonucleoprotein hnRNP U in the nuclear matrix". J. Cell. Biochem. 84 (3): 545–55. doi:10.1002/jcb.10047. PMID 11813259.

Further reading