GENOMIC CLONING AND STRUCTURAL-ANALYSIS OF THE MURINE POLYMERIC RECEPTOR (PIGR) GENE AND PROMOTER REGION

The role of the polymeric receptor (pIgR) is to transport polymeric Ig A across various mucosal epithelial layers. Although several mammalian pIgR cDNAs, including mouse, have been cloned, genomic structure has only been partially analyzed in the human, and neither its 5'-upstream region nor its transcriptional start site is known. We report the iso lation and characterization of the murine pIgR gene that spans 32 kb a nd contains 11 exons. The general organization of the murine gene, inc luding its intron/exon boundaries was similar to its human homolog; ho wever, the second intron was 7.2 kb in the mouse vs. only 0.8 kb in hu mans. Primer extension and 5'-RACE independently identified the identi cal transcriptional initiation site. Sequence analysis of 350 base pai rs in the 5'-flanking region revealed several motifs, including a TATA box, and putative interferon-gamma, HNF-3 beta and API sites. In summ ary, we have isolated the murine pIgR gene and described its structure and organization. (C) 1997 Elsevier Science B.V.