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- Beltcheva, O, et al.
(författare)
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Sp1 specifically binds to an evolutionarily conserved DNA segment within a region necessary for podocyte-specific expression of nephrin
- 2010
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Ingår i: Nephron. Experimental nephrology. - : S. Karger AG. - 1660-2129. ; 114:1, s. E15-E22
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Tidskriftsartikel (refereegranskat)abstract
- We have analyzed a conserved 237-bp segment located in a 1.9-kb upstream region of the nephrin gene, previously shown to contain kidney specific enhancer element(s). Electromobility shift assay was used to identify a 20-nucleotide region specifically recognized and bound by protein factors in nuclear extracts from immortalized podocyte and human embryonic kidney cell lines. The region was further narrowed down by competition assays to a stretch of 6 consecutive guanines, which are conserved at this location in multiple species. Introduction of mutations in this sequence abolished all protein binding activity whereas mutations in the flanking nucleotides did not. By means of gel supershift and chromatin immunoprecipitation assays we have shown that the protein factor from podocyte nuclear extracts able to recognize and bind the target sequence is the Sp1 zinc-finger protein.
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- Ito, Y, et al.
(författare)
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Wolf-Hirschhorn syndrome candidate 1-like 1 epigenetically regulates nephrin gene expression
- 2017
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Ingår i: American journal of physiology. Renal physiology. - : American Physiological Society. - 1522-1466 .- 1931-857X. ; 312:6, s. F1184-F1199
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Tidskriftsartikel (refereegranskat)abstract
- Altered expression of nephrin underlies the pathophysiology of proteinuria in both congenital and acquired nephrotic syndrome. However, the epigenetic mechanisms of nephrin gene regulation remain elusive. Here, we show that Wolf-Hirschhorn syndrome candidate 1-like 1 long form (WHSC1L1-L) is a novel epigenetic modifier of nephrin gene regulation. WHSC1L1-L was associated with histone H3K4 and H3K36 in human embryonic kidney cells. WHSC1L1-L gene was expressed in the podocytes, and functional protein product was detected in these cells. WHSC1L1-L was found to bind nephrin but not other podocyte-specific gene promoters, leading to its inhibition/suppression, abrogating the stimulatory effect of WT1 and NF-κB. Gene knockdown of WHSC1L1-L in primary cultured podocytes accelerated the transcription of nephrin but not CD2AP. An in vivo zebrafish study involving the injection of Whsc1l1 mRNA into embryos demonstrated an apparent reduction of nephrin mRNA but not podocin and CD2AP mRNA. Immunohistochemistry showed that both WHSC1L1-L and nephrin emerged at the S-shaped body stage in glomeruli. Immunofluorescence and confocal microscopy displayed WHSC1L1 to colocalize with trimethylated H3K4 in the glomerular podocytes. Chromatin immunoprecipitation assay revealed the reduction of the association of trimethylated H3K4 at the nephrin promoter regions. Finally, nephrin mRNA was upregulated in the glomerulus at the early proteinuric stage of mouse nephrosis, which was associated with the reduction of WHSC1L1. In conclusion, our results demonstrate that WHSC1L1-L acts as a histone methyltransferase in podocytes and regulates nephrin gene expression, which may in turn contribute to the integrity of the slit diaphragm of the glomerular filtration barrier.
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