title: UT-B Urea Transporter Localization in the Bovine Gastrointestinal Tract.
abstract: Facilitative UT-B urea transporters play an important role in the urea nitrogen salvaging process that occurs in the gastrointestinal tract of mammals, particularly ruminants. Gastrointestinal UT-B transporters have previously been reported in various ruminant species-including cow, sheep and goat. In this present study, UT-B transporter localization was investigated in tissues throughout the bovine gastrointestinal tract. RT-PCR analysis showed that UT-B2 was the predominant UT-B mRNA transcript expressed in dorsal, ventral and cranial ruminal sacs, while alternative UT-B transcripts were present in other gastrointestinal tissues. Immunoblotting analysis detected a strong, glycosylated ~50 kDa UT-B2 protein in all three ruminal sacs. Immunolocalization studies showed that UT-B2 protein was predominantly localized to the plasma membrane of cells in the stratum basale layer of all ruminal sac papillae. In contrast, other UT-B protein staining was detected in the basolateral membranes of the surface epithelial cells lining the abomasum, colon and rectum. Overall, these findings confirm that UT-B2 cellular localization is similar in all ruminal sacs and that other UT-B proteins are located in epithelial cells lining various tissues in the bovine gastrointestinal tract.
authors.affiliation: Room 2.55, School of Biology and Environmental Science, University College Dublin Science Centre West, Dublin 4, Ireland.
authors.forename: J
authors.initials: J
authors.lastname: Coyle
authors.affiliation: Room 2.55, School of Biology and Environmental Science, University College Dublin Science Centre West, Dublin 4, Ireland.
authors.forename: S
authors.initials: S
authors.lastname: McDaid
authors.affiliation: Room 2.55, School of Biology and Environmental Science, University College Dublin Science Centre West, Dublin 4, Ireland.
authors.forename: C
authors.initials: C
authors.lastname: Walpole
authors.affiliation: Room 2.55, School of Biology and Environmental Science, University College Dublin Science Centre West, Dublin 4, Ireland. gavin.stewart@ucd.ie.
authors.forename: Gavin S
authors.initials: GS
authors.lastname: Stewart
mesh_terms: D000818:Animals; D015415:Biomarkers; D002417:Cattle; D041981:Gastrointestinal Tract / Q000378:metabolism*; D015870:Gene Expression; D007150:Immunohistochemistry; D026901:Membrane Transport Proteins / Q000235:genetics / Q000378:metabolism*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D012417:Rumen / Q000378:metabolism; D000096982:Urea Transporters
chemical_list: D015415:Biomarkers; D026901:Membrane Transport Proteins; D012333:RNA, Messenger; D000096982:Urea Transporters
keywords: Cow; Gastrointestinal tract; Rumen; UT-B; Urea transporter