EXON INTRON ORGANIZATION, CHROMOSOME LOCALIZATION, ALTERNATIVE SPLICING, AND TRANSCRIPTION UNITS OF THE HUMAN APOLIPOPROTEIN-E RECEPTOR-2 GENE/

Apolipoprotein E receptor 2 is a recently identified receptor that res embles low and very low density lipoprotein receptors. Isolation and c haracterization of genomic clones encoding human apolipoprotein E rece ptor 2 revealed that the gene spans similar to 60 kilobases and contai ns 19 exons. The positions of the exon/intron boundaries of the gene a re almost identical to those of low and very low density lipoprotein r eceptors. Fluorescent in situ hybridization of human chromosomes revea led that the gene is located on chromosome 1p34. Isolation of a cDNA e ncoding a variant receptor and reverse transcription-polymerase chain reaction indicate the presence of multiple variants with different num bers of cysteine-rich repeats in the binding domain of the receptor. W e also found a variant receptor lacking a 59-amino acid insertion in t he cytoplasmic domain, The transcription start site was mapped to the position 236 base pairs upstream of the AUG translation initiator codo n by primer extension analysis, Sequence inspection of the 5'-flanking region revealed potential DNA elements: AP-2, GC factor, PEA3, and Sp 1. The minimal promoter region and a region required for nerve growth factor inducibility in PC12 cells were also determined.