Cell-free synthesis of rat alpha 2-macroglobulin and induction of its mRNA during experimental inflammation.
Poly(A)-rich RNA was isolated from the livers of acutely inflamed rats by extraction with guanidinium HCl and oligo(dT)-cellulose chromatography. After translation in a recticulocyte lysate and immunoprecipitation with a specific antiserum to alpha 2-macroglobulin a polypeptide with an apparent molecular weight of 162000 could be detected. The cell-free synthesis of alpha 2-macroglobulin was stimulated 8-fold by the addition of RNase inhibitor. Full-length alpha 2-macroglobulin polypeptide chains appeared after 35 min in the presence of 1.85 mM Mg2+ and 100 mM K+. A nucleotide number of about 5100 was estimated for alpha 2-macroglobulin by means of sucrose gradient centrifugation of poly(A)-rich RNA followed by translation in vitro and immunoprecipitation of alpha 2-macroglobulin. In normal liver alpha 2-macroglobulin mRNA represented about 0.0007% of total translatable RNA. Acute inflammation generated by intramuscular injection of turpentine led to a 66-fold increase in translatable alpha 2-macroglobulin mRNA after 18 h, followed by a rapid decrease. In accordance to the induction of alpha 2-macroglobulin mRNA serum concentrations of alpha 2-macroglobulin increased to about 2 mg/ml. Unlike alpha 2-macroglobulin mRNA serum alpha 2-macroglobulin levels remained unchanged up to 60 h.
D000818:Animals; D002474:Cell-Free System; D011232:Chemical Precipitation; D007120:Immunochemistry; D007249:Inflammation / Q000378:metabolism*; D008099:Liver / Q000378:metabolism; D008297:Male; D011061:Poly A / Q000096:biosynthesis; D014176:Protein Biosynthesis; D012333:RNA, Messenger / Q000096:biosynthesis*; D051381:Rats; D011919:Rats, Inbred Strains; D014425:Turpentine; D000511:alpha-Macroglobulins / Q000096:biosynthesis* / Q000235:genetics
D012333:RNA, Messenger; D000511:alpha-Macroglobulins; D011061:Poly A; D014425:Turpentine