Nucleic-acid-binding Properties of hnRNP-U/SAF-A, a Nuclear-Matrix Protein Which Binds DNA and RNA in Vivo and in Vitro

Eur J Biochem. 1994 Apr 15;221(2):749-57. doi: 10.1111/j.1432-1033.1994.tb18788.x.


We show that SAF-A, a nuclear protein which specifically binds vertebrate scaffold-attachment-region (SAR) elements with high affinity is identical with hnRNP-U, assumed to be involved in packaging of hnRNA in ribonucleoprotein particles. Ultraviolet cross-linking experiments show that the protein, referred to as hnRNP-U/SAF-A, is bound to chromosomal DNA in vivo. In vitro, the isolated protein binds to double-stranded and single-stranded DNA and forms higher ordered nucleic-acid-protein complexes. Filter-binding experiments performed with different types of natural and synthetic nucleic acids as substrates show that the protein binds DNA and RNA with different affinities and most likely at different binding sites. We conclude that hnRNP-U/SAF-A thus may have functions in the organisation of chromosomal DNA in addition to its suggested role in hnRNA metabolism.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Cell Nucleus / chemistry
  • DNA / metabolism*
  • DNA-Binding Proteins / analysis
  • DNA-Binding Proteins / metabolism*
  • HeLa Cells
  • Heterogeneous-Nuclear Ribonucleoprotein U
  • Heterogeneous-Nuclear Ribonucleoproteins
  • Humans
  • Molecular Sequence Data
  • RNA, Heterogeneous Nuclear / isolation & purification
  • RNA, Heterogeneous Nuclear / metabolism*
  • RNA-Binding Proteins / analysis
  • RNA-Binding Proteins / isolation & purification
  • RNA-Binding Proteins / metabolism*
  • Ribonucleoproteins / analysis
  • Ribonucleoproteins / isolation & purification
  • Ribonucleoproteins / metabolism*
  • Spectrophotometry, Ultraviolet


  • DNA-Binding Proteins
  • Heterogeneous-Nuclear Ribonucleoprotein U
  • Heterogeneous-Nuclear Ribonucleoproteins
  • RNA, Heterogeneous Nuclear
  • RNA-Binding Proteins
  • Ribonucleoproteins
  • DNA

Associated data

  • GENBANK/L23999