Extrahepatic synthesis of apolipoprotein E

Journal Article · Sat Dec 01 04:00:00 EST 1984 · J. Lipid Res.; (United States)

OSTI ID:5520594

Driscoll, D M; Getz, G S

Apolipoprotein E (apoE) synthesis has been examined in rat and guinea pig tissues using in vitro translation and (/sup 35/S)methionine labeling of tissue slices. A number of tissues not involved in lipoprotein synthesis synthesize a protein very similar to apoE, including the spleen, adrenal, kidney, testis, ovary, heart, and lung. Although the intestine is involved in lipoprotein synthesis, apoE synthesis could not be detected in intestinal mucosa. The protein synthesized by the extrahepatic tissues was identified as apoE by its electrophoretic mobility, its immunologic reactivity with a monospecific antibody and by limited proteolysis mapping with Staphylococcus aureus V8 protease. ApoE represented between 0.02 and 0.7% of the total protein synthesized in the extrahepatic tissues, indicating that apoE mRNA is a fairly abundant mRNA in these tissues. ApoE mRNA was also detected by hybridization with a rat apoE cDNA clone, which hybridized to a single mRNA 1250 nucleotides in length in rat liver and in extrahepatic tissues. Hybridization of the apoE clone to rat genomic DNA demonstrated that the apoE gene was more heavily methylated in intestinal mucosa, which did not synthesize apoE, than in liver, testis, or kidney. /sup 35/S labeling of peritoneal macrophages revealed that both rat and guinea pig macrophages synthesized and secreted apoE in vitro. Rhesus aortic smooth muscle cells also synthesized and secreted apoE. The possible functions of apoE synthesized in the peripheral tissues are considered.

• Research Organization: Univ. of Chicago, IL
• OSTI ID: 5520594
• Journal Information: J. Lipid Res.; (United States), Journal Name: J. Lipid Res.; (United States) Vol. 25:12; ISSN JLPRA
• Country of Publication: United States
• Language: English

Related Subjects

550201* -- Biochemistry-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
AMINO ACIDS
ANIMAL CELLS
ANIMALS
APOLIPOPROTEINS
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
BIOLOGICAL FUNCTIONS
BIOSYNTHESIS
BODY
CARBOXYLIC ACIDS
CONNECTIVE TISSUE CELLS
DAYS LIVING RADIOISOTOPES
DIGESTIVE SYSTEM
DNA
DRUGS
EVEN-ODD NUCLEI
FUNCTIONS
GASTROINTESTINAL TRACT
GLANDS
GONADS
GUINEA PIGS
HYBRIDIZATION
IN VITRO
INTESTINES
ISOTOPES
KIDNEYS
LABELLED COMPOUNDS
LIGHT NUCLEI
LIPIDS
LIPOPROTEINS
LIPOTROPIC FACTORS
LIVER
MACROPHAGES
MALE GENITALS
MAMMALS
MESSENGER-RNA
METHIONINE
MONKEYS
NUCLEI
NUCLEIC ACIDS
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC SULFUR COMPOUNDS
ORGANS
PHAGOCYTES
PRIMATES
PROTEINS
RADIOISOTOPES
RATS
RNA
RODENTS
SOMATIC CELLS
SULFUR 35
SULFUR COMPOUNDS
SULFUR ISOTOPES
SYNTHESIS
TESTES
VERTEBRATES