Molecular cloning of the cDNA encoding a human renal sodium phosphate transport protein and its assignment to chromosome 6p21.3-p23.
Resorption of phosphate by the kidney is an important function in the maintenance of phosphate homeostasis in mammals, and a defect in renal phosphate uptake has been implicated in at least three human genetic disorders. We have isolated a cDNA encoding a human sodium-dependent phosphate transport protein (NPT1). This cDNA hybridizes to a single 2.5-kb RNA transcript from human kidney cortex, its nucleotide sequence shows 80.3% identity to the rabbit NaPi-1 sequence, and it encodes a polypeptide of 467 amino acids. Amino acid sequence comparisons indicate a 69.7% identity between human NPT1 and rabbit NaPi-1 polypeptides; the inclusion of conservative substitutions increases the homology between the two proteins to 81.5%. Alignment of both sequences also reveals several conserved potential N-glycosylation and protein kinase C phosphorylation sites. Polypeptide hydropathy analysis predicts several membrane-spanning domains. This cDNA maps the location of the gene encoding NPT1 to human chromosome 6q21.3-p23.
Chong
S S
SS
Institute for Molecular Genetics, Baylor College of Medicine, Houston, Texas 77030.
Kristjansson
K
K
Zoghbi
H Y
HY
Hughes
M R
MR
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D015139:Blotting, Southern; D002352:Carrier Proteins / Q000235:genetics*; D002874:Chromosome Mapping; D002896:Chromosomes, Human, Pair 6; D003001:Cloning, Molecular; D004247:DNA; D006801:Humans; D006822:Hybrid Cells; D007668:Kidney / Q000378:metabolism*; D008969:Molecular Sequence Data; D011817:Rabbits; D012377:Rodentia; D017386:Sequence Homology, Amino Acid; D050608:Sodium-Phosphate Cotransporter Proteins; D050609:Sodium-Phosphate Cotransporter Proteins, Type I; D050611:Sodium-Phosphate Cotransporter Proteins, Type III; D027981:Symporters
D002352:Carrier Proteins; C493546:SLC17A1 protein, human; D050608:Sodium-Phosphate Cotransporter Proteins; D050609:Sodium-Phosphate Cotransporter Proteins, Type I; D050611:Sodium-Phosphate Cotransporter Proteins, Type III; D027981:Symporters; D004247:DNA