| Co-Investigator(Kenkyū-buntansha) |
KURE Shigeo Department of Medical Genetics, School of Medicine, Tohoku University, Associate Professor, 大学院・医学系研究科, 助教授 (10205221)
KONDO Yoshiaki Department of Pediatrics, School of Medicine, Tohoku University, Associate Professor, 大学院・医学系研究科, 助教授 (00221250)
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| Budget Amount *help |
¥3,200,000 (Direct Cost: ¥3,200,000)
Fiscal Year 2001: ¥1,300,000 (Direct Cost: ¥1,300,000)
Fiscal Year 2000: ¥1,900,000 (Direct Cost: ¥1,900,000)
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| Research Abstract |
Fanconi-Bickel syndrome (FBS) is an autosomal recessive disorder manifesting hepatorenal glycogen accumulation, Fanconi nephropathy, impaired utilization of glucose and galactose. Recently several mutations in a gene encoding a glucose transporter, GLUT2, have been reported in patients with FBS. Using PCR, direct sequencing, restriction fragment length analysis, and subcloning, we studied three Japanese patients and found four novel mutations : a splice-site mutation (IVS2-2A>G), a nonsense mutation (Q287X), and two missense mutations (L389P and V423E).
No previous reports have found that the heterozygotes with mutant GLUT2 to show renal glucosuria. The mother and brother of patient 1, who were heterozygous for the V423E mutation, manifested renal glucosuria. We speculate the possibility of GLUT2 as a candidate gene for familial renal glucosuria with incomplete penetrance. If some mutant GLUT2 proteins have a dominant-negative effect, an oligomer composed of mutant and wild-type proteins could result in abolition of transport activity.
To prove this hypothesis, we were trying to generate functional knockout of the GLUT2, and Fanconi-Bickel syndrome in mice expressing a dominant-negative GLUT2 subunit. To generate the GLUT2 dominant-negative construct, mutation were introduced to the cDNA sequence to change the valine (V) residue at position 423 to glutamate (E). For the transgene vector, GLUT2-V423E cDNA was inserted downstream of the CAG promotor. The expression unit (CDRE-GLUT2 : CAG-loxP-DsRed-loxP-IRES-EGFP) was excised, purified, and microinjected into fertilized eggs by standard procedure. Transgenic mice expressing GLUT2-V423E will be selected by analyzing urine sugar.
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