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Cloning and sequencing of human PEX from a bone cDNA library: evidence for its developmental stage-specific regulation in osteoblasts
- Source :
- Journal of bone and mineral research : the official journal of the American Society for Bone and Mineral Research. 12(7)
- Publication Year :
- 1997
-
Abstract
- Inactivating mutations of the neutral endopeptidase, PEX, have been identified as the cause of X-linked hypophosphatemia (XLH). Though the function of PEX is unknown, current information suggests that impaired renal phosphate conservation in XLH is due to the failure of PEX to either degrade an undefined phosphaturic factor or activate a novel phosphate-conserving hormone. The physiologically relevant target tissue for the XLH mutation has not been identified. An apparent intrinsic defect of osteoblast function in XLH implicates bone as a possible site of PEX expression. In the current investigation, we employed a polymerase chain reaction (PCR) strategy to amplify a PEX cDNA from a human bone cell cDNA library. We found that the human PEX cDNA encodes a 749 amino acid protein belonging to the type II integral membrane zinc-dependent endopeptidase family. The predicted PEX amino acid sequence shares 96.0% identity to the recently cloned mouse Pex cDNA and has 27–38% identity to other members of the metalloendopeptidase family. Using reverse transcriptase (RT)-PCR with PEX-specific primers, we detected PEX transcripts in both human osteosarcoma-derived MG-63 osteoblasts and in differentiated mouse MC3T3-E1 clonal osteoblasts but not in immature MC3T3-E1 preosteoblasts. The association of impaired mineralization of bone in XLH and the apparent developmental stage-specific expression of PEX in osteoblasts suggest that bone is a physiologically relevant site of PEX expression and that PEX may play an active role in osteoblast-mediated mineralization.
- Subjects :
- DNA, Complementary
X Chromosome
Genetic Linkage
Hypophosphatemia
Endocrinology, Diabetes and Metabolism
Molecular Sequence Data
Biology
Polymerase Chain Reaction
Cell Line
Mice
Complementary DNA
Gene expression
medicine
Animals
Humans
Orthopedics and Sports Medicine
Amino Acid Sequence
Cloning, Molecular
Peptide sequence
DNA Primers
Genetics
Osteoblasts
Base Sequence
cDNA library
PHEX
Gene Expression Regulation, Developmental
Proteins
Osteoblast
3T3 Cells
PHEX Phosphate Regulating Neutral Endopeptidase
Reverse transcriptase
Cell biology
medicine.anatomical_structure
Mutation
Metalloendopeptidase
Neprilysin
Subjects
Details
- ISSN :
- 08840431
- Volume :
- 12
- Issue :
- 7
- Database :
- OpenAIRE
- Journal :
- Journal of bone and mineral research : the official journal of the American Society for Bone and Mineral Research
- Accession number :
- edsair.doi.dedup.....1f484138e92ec29623b5a37ac944cfd8