Related Experiment Videos
[Recent progress in molecular biology of inherited tubular transport abnormalities]
Abstract:
Recent progress in the molecular biological approach to analysis of inherited tubular transport abnormalities is reviewed. 1) cDNAs of several mammalian proteins, related to amino acid transport in renal tubular cell, have been cloned using an expression cloning in Xenopus oocytes. One of them stimulates the transport of cystine, dibasic amino acids and neutral amino acids and will accelerate the analysis of cystinuria. 2) Isolation of cDNAs, encoding human and rat vasopressin V2 receptors, has been reported. The deduced amino acid sequence seems to be a member of receptors with seven putative transmembrane regions. Analysis of this gene from patients with nephrogenic diabetes insipidus is in progress. 3) Analysis of carbonic anhydrase II (CA II) gene in a Belgian family with renal tubular acidosis associated with osteoporosis and cerebral calcification has shown a point mutation replacing an invariant histidine residue of CA II protein with tyrosine. 4) Oculocerebrorenal syndrome of Lowe (OCRL) is a X-linked disorder affecting the lens, brain and kidneys. The OCRL locus has been mapped to Xq24-26 by linkage analysis and by finding de novo X-autosome translocations at Xq24-26 in two unrelated females with OCRL. A cDNA has been isolated using yeast artificial chromosome and DNA inserts that span the X chromosome breakpoint from a female patient. Transcript for this cDNA is absent in unrelated male patients. The open reading frame encodes a new protein similar to human inositol-polyphosphate-5-phosphatase, raising a possibility that OCRL is an inborn error of inositol phosphate metabolism.
Insights
Molecular biology advances are aiding the study of inherited kidney transport disorders. Cloning of amino acid transporters and vasopressin V2 receptors, alongside gene mutation analysis for carbonic anhydrase II and Lowe syndrome, offers new diagnostic and therapeutic insights.
Area of Science:
- Molecular biology
- Genetics
- Nephrology
Context:
- Inherited tubular transport abnormalities present complex diagnostic challenges.
- Molecular biological techniques offer novel approaches to understanding these conditions.
- Advances in gene cloning and sequencing are crucial for identifying disease mechanisms.
Purpose:
- To review recent molecular biological advancements in analyzing inherited tubular transport abnormalities.
- To highlight key findings in gene cloning and mutation analysis related to kidney function.
- To discuss the implications of these findings for understanding and diagnosing genetic kidney diseases.
Summary:
- Cloning of mammalian amino acid transporter cDNAs aids cystinuria analysis.
- Isolation of vasopressin V2 receptor cDNAs is underway for nephrogenic diabetes insipidus research.
- Mutation analysis of carbonic anhydrase II (CA II) gene identified a point mutation in a family with renal tubular acidosis.
- Oculocerebrorenal syndrome of Lowe (OCRL) locus mapped to Xq24-26, with a potential link to inositol phosphate metabolism.
Impact:
- Accelerated analysis of cystinuria through identification of a key amino acid transporter.
- Progress in understanding nephrogenic diabetes insipidus via V2 receptor gene analysis.
- Identification of a specific CA II gene mutation provides insights into renal tubular acidosis.
- Potential discovery of a new metabolic pathway involved in Lowe syndrome, impacting pediatric nephrology and genetics.