Molecular regulation of MHC class III (C4 and factor B) gene expression in mouse peritoneal macrophages

J Immunol. 1984 Sep;133(3):1618-26.


To study the molecular regulation of C4 and factor B synthesis in mouse peritoneal macrophages, mouse C4 cDNA clones isolated from an H-2d haplotype liver cDNA library, and a previously described mouse factor B cDNA clone, pBmB2 (9), were used to assess quantitative and qualitative differences in C4 and factor B mRNA in resident and elicited cells. The C4 clones that were isolated, pBmS2 (1 Kb) and pBmS10 (0.9 Kb), overlap and together span a 1.5 Kb coding region of mouse pro-C4, extending from the alpha-chain through the gamma-chain; four nucleotide substitutions are evident in comparing 316 bp of the sequence of clone pBmS10 to that of a previously described mouse C4 clone, pMLC4/w7-2 (23). By using these probes, Northern blot analysis of total cellular RNA revealed similar C4 mRNA levels in resident peritoneal macrophages from high-C4 (B10.A) and low-C4 (C3HeB) strains. Pulse and pulse-chase studies of C4 and factor B synthesis were performed on resident, starch-elicited, and thioglycollate-elicited peritoneal macrophages at two culture time periods, 0 to 9 and 24 to 33 hr, and total cellular RNA was isolated from each population at 4.5 and 28.5 hr of culture for Northern blot analysis of C4 and factor B mRNA content. The data demonstrate that as previously reported, C4 production decreases in elicited compared with resident macrophages and decreases with time in culture; however, factor B synthesis does not differ among resident and elicited cells and it increases with time in culture. The variations in C4 and factor B production by mouse peritoneal macrophages are not associated with alterations in C4 and factor B protein processing, catabolism, or secretion; rather, they are a function of differences in net amounts of C4 and factor B mRNA. These data provide direct evidence that the regulation of expression of these class III MHC genes in mouse peritoneal macrophages is a pretranslational event.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Autoradiography
  • Cloning, Molecular
  • Collodion
  • Complement C4 / biosynthesis*
  • Complement C4 / genetics
  • Complement Factor B / biosynthesis*
  • Complement Factor B / genetics
  • DNA / isolation & purification
  • Electrophoresis, Agar Gel
  • Enzyme Precursors / biosynthesis*
  • Female
  • Humans
  • Macrophage Activation
  • Macrophages / immunology
  • Macrophages / metabolism*
  • Macrophages / physiology
  • Male
  • Mice
  • Mice, Inbred Strains
  • Protein Biosynthesis*
  • RNA / isolation & purification


  • Complement C4
  • Enzyme Precursors
  • RNA
  • Collodion
  • DNA
  • Complement Factor B