Limits...
Molecular mechanism of regulation of OGG1: tuberin deficiency results in cytoplasmic redistribution of transcriptional factor NF-YA.

Habib SL - J Mol Signal (2009)

Bottom Line: Downregulation of tuberin results in a marked decrease of OGG1 and accumulation of oxidative DNA damage, (8-oxodG) in cultured cells.Downregulation of tuberin by siRNA resulted in a marked decrease in NF-YA and OGG1 protein expression in human renal epithelial cells.These data define a novel mechanism of regulation of OGG1 through tuberin.

View Article: PubMed Central - HTML - PubMed

Affiliation: South Texas Veterans Healthcare System, Geriatric Research, Education and Clinical Center, Department of Medicine, University of Texas Health Science Center, San Antonio, Texas 78229, USA.

ABSTRACT
The tuberous sclerosis complex (TSC) is caused by defects in one of two tumor suppressor genes, TSC-1 or TSC-2. TSC-2 gene encodes tuberin, a protein involved in the pathogenesis of kidney tumors, both angiomyolipomas and renal cell carcinomas. On the other hand, mice-deficient in the DNA repair enzyme OGG1 spontaneously develop adenoma and carcinoma. Downregulation of tuberin results in a marked decrease of OGG1 and accumulation of oxidative DNA damage, (8-oxodG) in cultured cells. In addition, tuberin haploinsufficiency is associated with the loss of OGG1 and accumulation of 8-oxodG in rat kidney tumor. Deficiency in tuberin results in decreased OGG1 and NF-YA protein expression and increased 8-oxodG in kidney tumor from TSC patients. In the current study, molecular mechanisms by which tuberin regulates OGG1 were explored. The deficiency of tuberin was associated with a significant decrease in NF-YA and loss of OGG1 in kidney tumors of Eker rat. Downregulation of tuberin by siRNA resulted in a marked decrease in NF-YA and OGG1 protein expression in human renal epithelial cells. Localization of NF-YA in wild type and tuberin-deficient cells was examined by western blot and immunostaining assays. In wild type cells, NF-YA was detected in the nucleus while in tuberin deficient cells in the cyotoplasm. Introducing adenovirus-expressing tuberin (Ad-TSC2) into tuberin-deficient cells restored the nuclear localization of NF-YA. These data define a novel mechanism of regulation of OGG1 through tuberin. This mechanism may be important in the pathogenesis of kidney tumors in patients with TSC disease.

No MeSH data available.


Related in: MedlinePlus

Downregulation of tuberin expression in human renal epithelial cells results in decrease in NF-YA and OGG1 expression. A. Immunoblot analysis of tuberin, NF-YA and OGG1 in HEK 293 cells transfected with siRNA directed against TSC2 for 48 h. Actin was used as a loading control. B. Histograms represent means ± SE (n = 2). Significant differences from cells transfected with the TSC2-specific siRNA are indicated by **P < 0.01.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC2807420&req=5

Figure 2: Downregulation of tuberin expression in human renal epithelial cells results in decrease in NF-YA and OGG1 expression. A. Immunoblot analysis of tuberin, NF-YA and OGG1 in HEK 293 cells transfected with siRNA directed against TSC2 for 48 h. Actin was used as a loading control. B. Histograms represent means ± SE (n = 2). Significant differences from cells transfected with the TSC2-specific siRNA are indicated by **P < 0.01.

Mentions: To explore the role of tuberin in the regulation of OGG1 expression, tuberin was first downregulated using specific siRNA against TSC2 gene in human renal epithelial cells. The cells transfected with the duplex siRNA oligonucleotide complementary to TSC2 had decreased tuberin protein expression compared to cells transfected with scrambled control oligonucleotides (Fig. 2). Downregulation of tuberin resulted in a decrease of NF-YA and OGG1 protein expression (Fig. 2).


Molecular mechanism of regulation of OGG1: tuberin deficiency results in cytoplasmic redistribution of transcriptional factor NF-YA.

Habib SL - J Mol Signal (2009)

Downregulation of tuberin expression in human renal epithelial cells results in decrease in NF-YA and OGG1 expression. A. Immunoblot analysis of tuberin, NF-YA and OGG1 in HEK 293 cells transfected with siRNA directed against TSC2 for 48 h. Actin was used as a loading control. B. Histograms represent means ± SE (n = 2). Significant differences from cells transfected with the TSC2-specific siRNA are indicated by **P < 0.01.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2807420&req=5

Figure 2: Downregulation of tuberin expression in human renal epithelial cells results in decrease in NF-YA and OGG1 expression. A. Immunoblot analysis of tuberin, NF-YA and OGG1 in HEK 293 cells transfected with siRNA directed against TSC2 for 48 h. Actin was used as a loading control. B. Histograms represent means ± SE (n = 2). Significant differences from cells transfected with the TSC2-specific siRNA are indicated by **P < 0.01.
Mentions: To explore the role of tuberin in the regulation of OGG1 expression, tuberin was first downregulated using specific siRNA against TSC2 gene in human renal epithelial cells. The cells transfected with the duplex siRNA oligonucleotide complementary to TSC2 had decreased tuberin protein expression compared to cells transfected with scrambled control oligonucleotides (Fig. 2). Downregulation of tuberin resulted in a decrease of NF-YA and OGG1 protein expression (Fig. 2).

Bottom Line: Downregulation of tuberin results in a marked decrease of OGG1 and accumulation of oxidative DNA damage, (8-oxodG) in cultured cells.Downregulation of tuberin by siRNA resulted in a marked decrease in NF-YA and OGG1 protein expression in human renal epithelial cells.These data define a novel mechanism of regulation of OGG1 through tuberin.

View Article: PubMed Central - HTML - PubMed

Affiliation: South Texas Veterans Healthcare System, Geriatric Research, Education and Clinical Center, Department of Medicine, University of Texas Health Science Center, San Antonio, Texas 78229, USA.

ABSTRACT
The tuberous sclerosis complex (TSC) is caused by defects in one of two tumor suppressor genes, TSC-1 or TSC-2. TSC-2 gene encodes tuberin, a protein involved in the pathogenesis of kidney tumors, both angiomyolipomas and renal cell carcinomas. On the other hand, mice-deficient in the DNA repair enzyme OGG1 spontaneously develop adenoma and carcinoma. Downregulation of tuberin results in a marked decrease of OGG1 and accumulation of oxidative DNA damage, (8-oxodG) in cultured cells. In addition, tuberin haploinsufficiency is associated with the loss of OGG1 and accumulation of 8-oxodG in rat kidney tumor. Deficiency in tuberin results in decreased OGG1 and NF-YA protein expression and increased 8-oxodG in kidney tumor from TSC patients. In the current study, molecular mechanisms by which tuberin regulates OGG1 were explored. The deficiency of tuberin was associated with a significant decrease in NF-YA and loss of OGG1 in kidney tumors of Eker rat. Downregulation of tuberin by siRNA resulted in a marked decrease in NF-YA and OGG1 protein expression in human renal epithelial cells. Localization of NF-YA in wild type and tuberin-deficient cells was examined by western blot and immunostaining assays. In wild type cells, NF-YA was detected in the nucleus while in tuberin deficient cells in the cyotoplasm. Introducing adenovirus-expressing tuberin (Ad-TSC2) into tuberin-deficient cells restored the nuclear localization of NF-YA. These data define a novel mechanism of regulation of OGG1 through tuberin. This mechanism may be important in the pathogenesis of kidney tumors in patients with TSC disease.

No MeSH data available.


Related in: MedlinePlus