title: Translated anti-sense product of the Na/phosphate co-transporter (NaPi-II).
abstract: The homeostasis of Pi in marine teleosts is maintained by renal Pi secretion as well as by Pi reabsorption. A Na/Pi co-transport system belonging to the NaPi-II protein family is instrumental in tightly controlled renal Pi handling in mammals and fish. We have isolated an NaPi-II related cDNA from winter flounder. It was cloned from a female gonad cDNA library and is 624 bp long. The transcript is expressed in female and male flounder gonads as well as in kidney and intestine, although at very low levels. RNase H digestion experiments revealed an opposite orientation of the transcript with regard to NaPi-II-related mRNA. The anti-sense orientation was confirmed by genomic sequence analysis and Southern blotting. Alluding to the sense transcript, the anti-sense transcript was denoted IPAN. The open reading frame of IPAN encodes a basic protein of 68 amino acid residues. Immunohistochemistry confined the anti-sense related protein, Ipan, to a submembranous compartment of immature oocytes, suggesting a role in oocyte development. In kidney and intestine Ipan is partly co-localized with the Na/Pi co-transporter, implying a regulatory function for the anti-sense protein. However, direct protein-protein interaction could not be established. The existence of a putative open reading frame in other species extends the biological significance of the novel protein.
authors.affiliation: Max-Planck-Institut für Molekulare Physiologie, Rheinlanddamm 201, 44139 Dortmund, Federal Republic of Germany.
authors.forename: B
authors.initials: B
authors.lastname: Huelseweh
authors.forename: B
authors.initials: B
authors.lastname: Kohl
authors.forename: H
authors.initials: H
authors.lastname: Hentschel
authors.forename: R K
authors.initials: RK
authors.lastname: Kinne
authors.forename: A
authors.initials: A
authors.lastname: Werner
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002352:Carrier Proteins / Q000235:genetics*; D016373:DNA, Antisense / Q000235:genetics*; D018076:DNA, Complementary / Q000737:chemistry; D005260:Female; D005432:Flounder; D015870:Gene Expression / Q000235:genetics; D006066:Gonads / Q000737:chemistry; D007150:Immunohistochemistry; D008297:Male; D008969:Molecular Sequence Data; D009865:Oocytes / Q000378:metabolism; D014176:Protein Biosynthesis / Q000235:genetics*; D012333:RNA, Messenger / Q000235:genetics; D016914:Ribonuclease H / Q000378:metabolism; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA; D050608:Sodium-Phosphate Cotransporter Proteins; D027981:Symporters; D014158:Transcription, Genetic / Q000235:genetics; D014982:Xenopus laevis
chemical_list: D002352:Carrier Proteins; D016373:DNA, Antisense; D018076:DNA, Complementary; D012333:RNA, Messenger; D050608:Sodium-Phosphate Cotransporter Proteins; D027981:Symporters; D016914:Ribonuclease H