1996 Fiscal Year Final Research Report Summary
Molecular biological examination of Calcium-sensitive Chloride Channel expressed in the kidney
| Project/Area Number |
07671242
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Kidney internal medicine
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| Research Institution | Tokyo Medical and Dental University |
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Principal Investigator |
SAKAMOTO Hisato Tokyo Medical and Dental University, School of Medicine, Instructor, 医学部, 助手 (80187046)
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| Co-Investigator(Kenkyū-buntansha) |
UCHIDA Shinichi Tokyo Medical and Dental University, School of Medicine, Instructor, 医学部, 助手 (50262184)
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| Project Period (FY) |
1995 – 1996
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| Keywords | chloride / channel / cloning / patch-clamp / kidney / molecular biology |
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| Research Abstract |
A new chloride channel that belongs to ClC chloride channel family has been identified from rat kidney by a sequence homology-based strategy and designated as ClC-5, ClC-5 cDNA encodes a polypeptide of 746 amino acids, which is indicated by hydrophobicity analysis to have structural features that are common of the ClC family. Northern blot analysis of rat tissues showed that ClC-5 mRNA was predominantly expressed in the kidney and colon. According to the phylogenic analysis ClC-5 chloride channel can be classified into a subfamily : the ClC-3/ClC-4/ClC-5 chloride channels. To characterized the functional properties of ClC-5 by patch-clamp technique, we established the stably transfected cultured cells line using intranuclear microinjection technique. The transfected cells induced out-wardly rectifying chloride currents (ORCC) on whole cell configuration as same as that of ClC-3. In addition, the properties of ClC-5 channel have been examined at the level of single channel using the inside-out patch technique. In addition, when we have identified the ClC-5 from rat kidney, human ClCN5 cDNA which was counterpart of rat ClC-5 has been independently reported as a candidate gene for three different inherited kidney diseases (Dent's disease, X-linked recessive nephrolithiasis, and X-linked recessive hypophosphataemic rickets). In the clinical approach, the mutations in ClCN5 gene were also identified from three patients associated with idiopathic low-molecular-weight proteinuria. However, it is not clear how loss of this renal chloride channel can result in diverse renal dysfunction in these disease. Now, ClC-5 has attracted a special interest in relation to these hereditary renal disease. To examine the molecular structure and functional properties of ClC-5 will provide an important insight into these pathogenesis of these inherited disease associated with common molecular abnormalities of ClCN5 gene.
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