Distribution of apolipoprotein A-I, C-II, C-III, and E mRNA in fetal human tissues. Time-dependent induction of apolipoprotein E mRNA by cultures of human monocyte-macrophages.
Recently developed molecular probes for human apolipoprotein (apo) genes have been used to study the specificity of human tissue expression of the apo A-I, apo C-II, apo C-III, and apo E genes. We have found that apo E mRNA was present in all tissues examined. On the basis of total RNA concentration the relative abundance of apo E mRNA expressed as a percentage of the liver value is as follows: adrenal gland and macrophages, 74-100%; gonads and kidney, 12-15%; spleen, brain, thymus, ovaries, intestine, and pancreas, 3-9%; heart, 1.5%; stomach, striated muscle, and lung, less than 1%. The relative concentration of apo E mRNA in cultures of human peripheral blood monocyte-macrophages increases dramatically as a function of time in culture, and after 5 days, it compares to that of liver. The human tissues shown to synthesize apo E mRNA were also examined for their ability to synthesize apo A-I, apo C-II, and apo C-III mRNA. The relative abundance of apo A-I, apo C-III, and apo C-II mRNA expressed as a percentage of the liver value is as follows: apo A-I, intestine, 50%; apo A-I, pancreas and gonads, 12%; apo A-I, kidney, 4%; apo A-I, adrenal, 2.5%; apo A-I, ovaries and heart, 1%; apo A-I, stomach and thymus, less than 1%; apo C-III, intestine, 62%; apo C-III, pancreas, 7%; apo C-II, intestine, 3%; apo C-II, pancreas, less than 1%. The knowledge of tissue specificities in the synthesis of apolipoproteins is important for our understanding of the regulation of apolipoproteins and lipoprotein metabolism.
D016632:Apolipoprotein A-I; D053304:Apolipoprotein C-II; D053305:Apolipoprotein C-III; D001054:Apolipoproteins A / Q000235:genetics*; D001056:Apolipoproteins C / Q000235:genetics*; D002478:Cells, Cultured; D003001:Cloning, Molecular; D004247:DNA / Q000235:genetics; D005260:Female; D005333:Fetus; D006801:Humans; D008075:Lipoproteins, HDL / Q000235:genetics*; D008264:Macrophages / Q000166:cytology / Q000378:metabolism*; D009000:Monocytes / Q000166:cytology / Q000378:metabolism*; D009693:Nucleic Acid Hybridization; D011247:Pregnancy; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics*; D013698:Templates, Genetic
D016632:Apolipoprotein A-I; D053304:Apolipoprotein C-II; D053305:Apolipoprotein C-III; D001054:Apolipoproteins A; D001056:Apolipoproteins C; D008075:Lipoproteins, HDL; D012333:RNA, Messenger; D004247:DNA