Cadmium down-regulation of kidney Sp1 binding to mouse SGLT1 and SGLT2 gene promoters: Possible reaction of cadmium with the zinc finger domain of Sp1

Journal Article · Sat May 01 00:00:00 EDT 2010 · Toxicology and Applied Pharmacology

DOI:https://doi.org/10.1016/j.taap.2009.12.038· OSTI ID:21344927

Kothinti, Rajendra K; Blodgett, Amy B; Petering, David H ^[1]

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1. Department of Chemistry and Biochemistry, University of Wisconsin-Milwaukee, Milwaukee, WI 53201 (United States)

Cadmium (Cd) exposure causes glucosuria (glucose in the urine). Previously, it was shown that Cd exposure of primary cultures of mouse kidney cells (PMKC) decreased mRNA levels of the glucose transporters, SGLT1 and SGLT2 and that Sp1 from Cd-exposed cells displayed reduced binding to the GC boxes of the mouse SGLT1 promoter in vitro. Here, we identified a GC box upstream of mouse SGLT2 gene. ChIP assays on PMKC revealed that exposure to 5 muM Cd abolished Sp1 binding to SGLT1 GC box while it decreased Sp1 binding to SGLT2 GC sequence by 30% in vivo. The in vitro DNA binding assay, EMSA, demonstrated that binding of Sp1 from Cd (7.5 muM)-treated PMKC to the SGLT2 GC probe was 86% lower than in untreated cells. Sp1 is a zinc finger protein. Compared to PMKC exposed to 5 muM Cd alone, inclusion of 5 muM Zn restored SGLT1 and 2 mRNA levels by 15% and 30%, respectively. Cd (10 muM) decreased the binding of recombinant Sp1 (rhSp1) to SGLT1 and SGLT2 GC probes to 12% and 8% of untreated controls. Cd exerted no effect on GC-bound rhSp1. Co-treatment with Cd and Zn showed that added Zn significantly restored rhSp1 binding to the SGLT1 and SGLT2. Addition of Zn post Cd treatment was not stimulatory. We conclude that Cd can replace Zn in Sp1 DNA binding domain to reduce its binding to GC sites in mouse SGLT1 and SGLT2 promoters.

• OSTI ID: 21344927
• Journal Information: Toxicology and Applied Pharmacology, Vol. 244, Issue 3; Other Information: DOI: 10.1016/j.taap.2009.12.038; PII: S0041-008X(10)00003-7; Copyright (c) 2010 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; ISSN 0041-008X
• Country of Publication: United States
• Language: English

Related Subjects

60 APPLIED LIFE SCIENCES
CADMIUM
CYSTEINE
GENES
GLUCOSE
IN VITRO
IN VIVO
KIDNEYS
MESSENGER-RNA
MICE
PROMOTERS
URINE
ZINC
ALDEHYDES
AMINO ACIDS
ANIMALS
BIOLOGICAL MATERIALS
BIOLOGICAL WASTES
BODY
BODY FLUIDS
CARBOHYDRATES
CARBOXYLIC ACIDS
ELEMENTS
HEXOSES
MAMMALS
MATERIALS
METALS
MONOSACCHARIDES
NUCLEIC ACIDS
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC SULFUR COMPOUNDS
ORGANS
RNA
RODENTS
SACCHARIDES
THIOLS
VERTEBRATES
WASTES