title: Cloning and characterization of the bovine polymeric immunoglobulin receptor-encoding cDNA.
abstract: Trans-epithelial transport of polymeric immunoglobulins (pIg) into mucosal and glandular secretions is carried out by the pIg receptor (pIgR). Therefore, expression of the pIgR gene in epithelial cells of mucosal and glandular tissues is an absolute requirement for achieving mucosal immunity. We report the cloning and characterization of the bovine pIgR cDNA. Three overlapping cDNA clones with a total length of 3608 bp yielded an open reading frame encoding a 757-amino-acid (aa) transmembrane (TM) glycoprotein. Although polymorphism was found in two separate clones, Northern blot analysis showed a single pIgR mRNA (approx. 3.8 kb) to be present in the mammary gland, liver, lung, kidney and intestine of a lactating cow. There was no detectable expression of pIgR in the spleen of the same animal. Comparison of the deduced bovine pIgR as sequence with those of rat, mouse, man and rabbit shows that this receptor is highly conserved both in aa sequence and structural organization. The degree of conservation in the TM sequence and the C-terminal cytoplasmic tail, which contains the various signals for intracellular trafficking of the receptor, is 65-73%. We also find a high degree of conservation (61-66%) in the ectoplasmic part of the receptor, known as the secretory component (SC), with an exception for that of the rabbit SC, which is much lower (47%). Among the five Ig-like domains in the SC, the N-terminal domain I, where the primary pIg-binding site is located, showed the highest (72-83%) aa sequence conservation.
authors.affiliation: Leiden Institute of Chemistry, Medical Biotechnology Department, Gorlaeus Laboratories, Leiden University, The Netherlands.
authors.forename: M P
authors.initials: MP
authors.lastname: Verbeet
authors.forename: H
authors.initials: H
authors.lastname: Vermeer
authors.forename: G C
authors.initials: GC
authors.lastname: Warmerdam
authors.forename: H A
authors.initials: HA
authors.lastname: de Boer
authors.forename: S H
authors.initials: SH
authors.lastname: Lee
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D002417:Cattle / Q000235:genetics*; D003001:Cloning, Molecular; D016384:Consensus Sequence; D017124:Conserved Sequence; D018076:DNA, Complementary; D015870:Gene Expression; D006801:Humans; D051379:Mice; D008969:Molecular Sequence Data; D016366:Open Reading Frames; D011110:Polymorphism, Genetic; D012333:RNA, Messenger / Q000096:biosynthesis; D011817:Rabbits; D051381:Rats; D019056:Receptors, Polymeric Immunoglobulin / Q000096:biosynthesis* / Q000235:genetics*; D017386:Sequence Homology, Amino Acid; D013045:Species Specificity; D014158:Transcription, Genetic
chemical_list: D018076:DNA, Complementary; D012333:RNA, Messenger; D019056:Receptors, Polymeric Immunoglobulin