CLONING OF A COMPLEMENTARY DEOXYRIBONUCLEIC-ACID ENCODING THE MURINE HOMOLOG OF THE VERY-LOW-DENSITY LIPOPROTEIN APOLIPOPROTEIN-E RECEPTOR - EXPRESSION PATTERN AND ASSIGNMENT OF THE GENE TO MOUSE CHROMOSOME-19

We report the cloning of a complementary DNA for the mouse homolog of the very low density lipoprotein (VLDL)/apolipoprotein-E receptor (VLD LR), the deduced amino acid sequence of the protein, and the mapping o f the gene encoding the receptor to mouse chromesome 19. Northern hybr idization revealed that the VLDLR messenger RNA (mRNA) is most abundan t in skeletal muscle, heart, kidney, and brain. It was also detected i n lung and in low levels in liver, but it was not found in spleen or t estes. Levels of VLDLR mRNA in mouse placenta increased from days 8-18 of gestation. The VLDLR mRNA was induced in 3T3-L1 cells undergoing d ifferentiation into adipocytes. The increase in VLDLR mRNA paralleled the rise in lipoprotein lipase and hormone-sensitive lipase mRNAs. How ever, VLDLR and low density lipoprotein receptor-related protein were increased in the presence of retinoic acid, whereas the induction of l ipoprotein lipase and hormone-sensitive lipase mRNAs was inhibited. Ou r observations demonstrate regulated expression of the VLDLR gene in p lacenta and adipocytes, where the receptor protein may play roles in t he uptake of triglyceride-rich particles for storage of lipid (adipocy tes) or for lipid transport to the fetus (placenta). The availability of a murine complementary DNA probe and the knowledge of the map posit ion of the VLDLR gene in the mouse genome will facilitate studies on t he function and regulation of this protein.