Pentraxin binding to isolated rat liver nuclei

E. G. Shephard, P. J. Smith, T. S. Coetzee, A. F. Strachan, F. C. de Beer

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9 Scopus citations

Abstract

The interaction of human C-reactive protein (CRP) and serum amyloid P-component (SAP) with isolated rat liver nuclei was studied to identify nuclear ligands for each pentraxin using the iodinatable heterobifunctional thiol-cleavable crosslinking reagent sulphosuccinimidyl-2 -(p- azidosalicylamido)-1,3'-dithiopropionate (SASD). Nuclei (100 μg of DNA) bound 21 pmol of 125I-labelled CRP Ca2+-dependently at saturation with half-saturation occurring at 200 pmol of 125I-CRP. By contrast, only 2.7 pmol of 125I-labelled SAP was bound at saturation, with half-saturation at 50 pmol. The binding of pentraxins to nuclei is, in addition to putative chromatin binding, due to nuclear-envelope binding, where 3.2 pmol 125I-labelled CRP binds Ca2+ dependently to nuclear envelopes (25 μg) at saturation, but only 0.62 pmol SAP is required to saturate. Specific photocross-linking of 125I-2-(p-azidosalicylamido)-1,3'-dithiopropionate (125I-ASD)-CRP and 125I-ASD-SAP to nuclei revealed transfer of 125I-photoreactive azides to nuclear-envelope proteins of 43, 46, 52 and 70 kDa. In addition, SAP binding to histones H2A, H2B, H3 and H4 was detected, whereas CRP bound only to H4. Neither pentraxin cross-linked to histone H1.

Original languageEnglish
Pages (from-to)257-262
Number of pages6
JournalBiochemical Journal
Volume279
Issue number1
DOIs
StatePublished - 1991

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology

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