Molecular cloning and functional characterization of a cDNA encoding nucleosome assembly protein 1 (NAP-1) from soybean

Mol Gen Genet. 1995 Dec 15;249(5):465-73. doi: 10.1007/BF00290572.


NAP-1, a protein first isolated from mammalian cells, can introduce supercoils into relaxed circular DNA in the presence of purified core histones. Based on its in vitro activity, it has been suggested that NAP-1 may be involved in nucleosome assembly in vivo. We isolated a cDNA clone encoding a soybean NAP-1 homolog, SNAP-1. The SNAP-1 cDNA contains an open reading frame of 358 amino acids residues with a calculated molecular weight of 41 kDa. The deduced amino acid sequence of SNAP-1 shares sequence similarity with yeast NAP-1 (38%) and human hNRP (32%). Notable features of the deduced sequence are two extended acidic regions thought to be involved in histone binding. SNAP-1 expressed in Escherichia coli induces supercoiling in relaxed circular DNA, suggesting that SNAP-1 may have nucleosome assembly activity. The specific activity of SNAP-1 is comparable to that of HeLa NAP-1 in an in vitro assay. Western analysis reveals that SNAP-1 is expressed in the immature and young tissues that were examined, while mature tissues such as old leaves and roots, show very little or no expression. NAP-1 homologs also appear to be present in other plant species.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Base Sequence
  • Cell Cycle Proteins
  • Cloning, Molecular
  • DNA, Circular / metabolism
  • DNA, Complementary
  • DNA, Plant
  • Escherichia coli
  • HeLa Cells
  • Histones / metabolism
  • Humans
  • Molecular Sequence Data
  • Nuclear Proteins
  • Nucleosome Assembly Protein 1
  • Nucleosomes / metabolism*
  • Plant Proteins / chemistry
  • Plant Proteins / genetics*
  • Plant Proteins / isolation & purification
  • Plant Proteins / metabolism
  • Proteins / chemistry
  • Proteins / genetics*
  • Proteins / metabolism
  • Soybeans / chemistry
  • Soybeans / genetics*


  • Cell Cycle Proteins
  • DNA, Circular
  • DNA, Complementary
  • DNA, Plant
  • Histones
  • NAP1L1 protein, human
  • Nuclear Proteins
  • Nucleosome Assembly Protein 1
  • Nucleosomes
  • Plant Proteins
  • Proteins

Associated data

  • GENBANK/L38856