Transcriptional regulation of PDGF-A and TGF-beta by +KTS WT1 deletion mutants and a mutant mimicking Denys-Drash syndrome.
Denys-Drash syndrome (DDS) and Frasier syndrome (FS) are rare diseases caused by the mutations of Wilms tumor gene, WT1. The common denominator in these syndromes is a nephropathy which is manifested by early-onset proteinuria, nephrotic syndrome and end stage renal failure. Although these syndromes are genetic models of nephropathy and the mutations of WT1 gene are characterized in these patients the mechanism how mutations of WT1 gene affect the embryonic kidney adversely has not been elucidated. Recently, there was a report that FS is caused by mutations in the donor splice site of WT1. These mutations predicted loss of +KTS isoform, which is one of the four splicing variants of WT1. In this study, two +KTS deletion mutants of WT1 were made as well as a WT1 mutant mimicking a mutation found in a patient who had diffuse mesangial sclerosis, end stage renal failure and Wilms tumor. Mutant embryonic kidney cell lines were established by transfection of 293 embryonic kidney cells with WT1 mutants. We investigated the transcription regulation of mutant WT1 among these cell lines using the reporter vectors containing PDGF-A and TGF-beta promoter sequence. Our results showed that the promoter activity of PDGF-A and TGF-beta, which are related to the progression of glomerular diseases, was modestly increased in the mutant cell mimicking the patent, while those activities were markedly increased in other two deletion mutant cell lines. This study demonstrated that +KTS WT1 mutation found in DDS affected the cytokine expression adversely in vitro. From these results, we suggest that the alteration of +KTS WT1 expression be responsible for the rapid progression of renal diseases in DDS and FS.
Jin
D K
DK
Department of Pediatrics, Samsung Medical Center, Sungkyunkwan University, School of Medicine, Seoul, Korea. jindk@smc.samsung.co.kr
Kang
S J
SJ
Kim
S J
SJ
Bang
E H
EH
Hwang
H Z
HZ
Tadokoro
K
K
Yamada
M
M
Kohsaka
T
T
D002675:Child, Preschool; D002872:Chromosome Deletion; D006801:Humans; D007674:Kidney Diseases / Q000235:genetics; D007680:Kidney Neoplasms / Q000235:genetics*; D008297:Male; D009154:Mutation; D010982:Platelet-Derived Growth Factor / Q000235:genetics*; D013577:Syndrome; D014158:Transcription, Genetic; D016212:Transforming Growth Factor beta / Q000235:genetics*; D009396:Wilms Tumor / Q000235:genetics*
D010982:Platelet-Derived Growth Factor; D016212:Transforming Growth Factor beta; C075278:platelet-derived growth factor A