title: Expression of dipeptidyl peptidase IV in rat tissues is mainly regulated at the mRNA levels.
abstract: Dipeptidyl peptidase IV (DPPIV) is a serine peptidase that cleaves N-terminal dipeptides from polypeptides when the second residue is a proline or an alanine. We have recently cloned cDNAs for rat gp110, a membrane glycoprotein with Mr of 110,000 isolated initially from rat liver. Studies reported here establish that the gp110 for which we have cloned cDNAs is DPPIV. Using the antibodies against and cDNA for DPPIV, we have assessed the tissue distribution of DPPIV by molecular approaches. Immunoblot analysis demonstrated that DPPIV is present in the kidney, lung, and small intestine at high levels, in the liver and spleen at moderate levels, and in the heart at low levels. The highest levels of mRNA for DPPIV were detected in the kidney and small intestine as compared to moderate levels found in the lung, liver, and spleen. The lowest levels of DPPIV mRNA were found in the stomach, testis, and heart. No detectable DPPIV protein and mRNA were found in brain or muscle. LDPPIV protein and mRNA are present at much lower levels in fetal livers as compared to the adult liver. Indirect immunofluorescence microscopy demonstrated that DPPIV is localized in the bile canaliculus of hematocytes and in the apical membrane domains of kidney tubule and small intestine. Further studies by Southern blot analysis indicate that DPPIV is encoded by a single gene.
authors.affiliation: Department of Biological Sciences, State University of New York, Buffalo 14260.
authors.forename: W J
authors.initials: WJ
authors.lastname: Hong
authors.forename: J K
authors.initials: JK
authors.lastname: Petell
authors.forename: D
authors.initials: D
authors.lastname: Swank
authors.forename: J
authors.initials: J
authors.lastname: Sanford
authors.forename: D C
authors.initials: DC
authors.lastname: Hixson
authors.forename: D
authors.initials: D
authors.lastname: Doyle
mesh_terms: D000818:Animals; D015139:Blotting, Southern; D003001:Cloning, Molecular; D018819:Dipeptidyl Peptidase 4; D004152:Dipeptidyl-Peptidases and Tripeptidyl-Peptidases / Q000235:genetics*; D005786:Gene Expression Regulation; D005796:Genes; D007158:Immunologic Techniques; D007421:Intestine, Small / Q000201:enzymology; D007668:Kidney / Q000201:enzymology; D008099:Liver / Q000201:enzymology / Q000254:growth & development; D008562:Membrane Glycoproteins / Q000235:genetics; D012333:RNA, Messenger / Q000235:genetics; D051381:Rats; D014018:Tissue Distribution
chemical_list: D008562:Membrane Glycoproteins; D012333:RNA, Messenger; D004152:Dipeptidyl-Peptidases and Tripeptidyl-Peptidases; D018819:Dipeptidyl Peptidase 4