Expression of aldolase isozyme mRNAs in fetal rat liver.
The regulation of aldolase isozyme expression during development was studied by measuring the concentrations of mRNAs coding for aldolase A and B subunits in fetal and adult rat liver. Poly(A)-containing RNAs were extracted from livers at various stages of development of fetal rats, and the aldolase A and B subunits in the in vitro translation products of these RNAs were analyzed immunologically. The content of aldolase B mRNA in 14-day fetal liver, measured quantitatively as translational activity, was somewhat smaller than that of aldolase A mRNA; immunologically precipitable aldolase B and A amounted to 0.06% and 0.25% respectively, of the total products. Similar experiments using RNAs from fetuses at later stages, however, showed that aldolase B mRNA increased during development, whereas aldolase A mRNA decreased. In newborn rat liver, aldolase B constituted 0.56% of the total translation products of mRNA, but there was little detectable aldolase A (0.03%). The changes of aldolase mRNA levels were analyzed further by northern blot and dot-blot hybridization experiments using cloned aldolase A and B cDNAs. The content of aldolase B mRNA increased in the fetal stage, and that in newborn rat liver was about 12 times that in 14-day fetal liver. In contrast, the aldolase A mRNA content decreased during gestation and that in newborn rat liver was about one-eighth of that in 14-day fetal liver. These observations suggest that the switch of aldolase isozyme expression in fetal liver is controlled by the levels of the respective mRNAs.
D000818:Animals; D002474:Cell-Free System; D003001:Cloning, Molecular; D004247:DNA / Q000235:genetics*; D005260:Female; D005333:Fetus; D005634:Fructose-Bisphosphate Aldolase / Q000032:analysis / Q000235:genetics*; D005786:Gene Expression Regulation; D007527:Isoenzymes / Q000032:analysis / Q000235:genetics*; D008099:Liver / Q000201:enzymology*; D008297:Male; D009693:Nucleic Acid Hybridization; D011233:Precipitin Tests; D014176:Protein Biosynthesis; D012333:RNA, Messenger / Q000235:genetics*; D051381:Rats; D011919:Rats, Inbred Strains
D007527:Isoenzymes; D012333:RNA, Messenger; D004247:DNA; D005634:Fructose-Bisphosphate Aldolase