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Arsenite Exposure Displaces Zinc from ZRANB2 Leading to Altered Splicing
- Source :
- Chem Res Toxicol
- Publication Year :
- 2020
- Publisher :
- American Chemical Society (ACS), 2020.
-
Abstract
- Exposure to arsenic, a class I carcinogen, affects 200 million people globally. Skin is the major target organ, but the molecular etiology of arsenic-induced skin carcinogenesis remains unclear. Arsenite (As3+)-induced disruption of alternative splicing could be involved, but the mechanism is unknown. Zinc finger proteins play key roles in alternative splicing. As3+ can displace zinc (Zn2+) from C3H1 and C4 zinc finger motifs (zfm's), affecting protein function. ZRANB2, an alternative splicing regulator with two C4 zfm's integral to its structure and splicing function, was chosen as a candidate for this study. We hypothesized that As3+ could displace Zn2+ from ZRANB2, altering its structure, expression, and splicing function. As3+/Zn2+ binding and mutual displacement experiments were performed with synthetic apo-peptides corresponding to each ZRANB2 zfm, employing a combination of intrinsic fluorescence, ultraviolet spectrophotometry, zinc colorimetric assay, and liquid chromatography-tandem mass spectrometry. ZRANB2 expression in HaCaT cells acutely exposed to As3+ (0 or 5 μM, 0-72 h; or 0-5 μM, 6 h) was examined by RT-qPCR and immunoblotting. ZRANB2-dependent splicing of TRA2B mRNA, a known ZRANB2 target, was monitored by reverse transcription-polymerase chain reaction. As3+ bound to, as well as displaced Zn2+ from, each zfm. Also, Zn2+ displaced As3+ from As3+-bound zfm's acutely, albeit transiently. As3+ exposure induced ZRANB2 protein expression between 3 and 24 h and at all exposures tested but not ZRANB2 mRNA expression. ZRANB2-directed TRA2B splicing was impaired between 3 and 24 h post-exposure. Furthermore, ZRANB2 splicing function was also compromised at all As3+ exposures, starting at 100 nm. We conclude that As3+ exposure displaces Zn2+ from ZRANB2 zfm's, changing its structure and compromising splicing of its targets, and increases ZRANB2 protein expression as a homeostatic response both at environmental/toxicological exposures and therapeutically relevant doses.
- Subjects :
- Arsenites
Cell Survival
010501 environmental sciences
Toxicology
01 natural sciences
Article
Cell Line
03 medical and health sciences
chemistry.chemical_compound
Humans
Carcinogen
030304 developmental biology
0105 earth and related environmental sciences
Arsenite
Zinc finger
0303 health sciences
Messenger RNA
Chemistry
Alternative splicing
RNA-Binding Proteins
General Medicine
Cell biology
Alternative Splicing
Zinc
HaCaT
RNA splicing
Environmental Pollutants
Homeostasis
Subjects
Details
- ISSN :
- 15205010 and 0893228X
- Volume :
- 33
- Database :
- OpenAIRE
- Journal :
- Chemical Research in Toxicology
- Accession number :
- edsair.doi.dedup.....bf8816c61516e4742d4d834a4859062c