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Alternative splicing variants of human arsenic (+3 oxidation state) methyltransferase.
MedLine Citation:
PMID:  22005461     Owner:  NLM     Status:  Publisher    
Abstract/OtherAbstract:
Arsenic (+3 oxidation state) methyltransferase (As3MT) catalyzes the methylation of trivalent arsenic (As(III)) to monomethylarsonate (MMA(V)) and dimethylarsinic acid (DMA(V)), and plays an important role in the detoxification of arsenicals. Here, we report the identification of two splicing variants of the human As3MT gene. One splicing variant was an exon-3 skipping (Δ3) form which produced a premature stop codon, and the other was an exon-4 and -5 skipping (Δ4,5) form which produced a 31.1kDa As3MT protein. In addition to the full-length mRNA of As3MT, Δ4,5 mRNAs were detected in HepG2, A549, HL60, K562, and HEK293 cells. The methyltransferase activity of the recombinant Δ4,5 As3MT and wild-type As3MT proteins purified from Escherichia coli was determined. Speciation analysis by HPLC-ICP-MS showed a clear peak of MMA(V) after incubation of As(III) with the wild-type As3MT protein, but not with the Δ4,5 As3MT protein. In addition, COS-7 cells transfected with Δ4,5 As3MT cDNA did not convert As(III) to MMA(V) or DMA(V). The lack of methyltransferase activity of Δ4,5 As3MT seems to be related to the deletion of an S-adenosylmethionine-binding site and a critical cysteine residue. These data suggest that the expression pattern of splicing variants of the As3MT gene may affect the capacity for arsenic methylation in cells.
Authors:
Daigo Sumi; Kayo Fukushima; Hideki Miyataka; Seiichiro Himeno
Publication Detail:
Type:  JOURNAL ARTICLE     Date:  2011-10-8
Journal Detail:
Title:  Biochemical and biophysical research communications     Volume:  -     ISSN:  1090-2104     ISO Abbreviation:  -     Publication Date:  2011 Oct 
Date Detail:
Created Date:  2011-10-18     Completed Date:  -     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  0372516     Medline TA:  Biochem Biophys Res Commun     Country:  -    
Other Details:
Languages:  ENG     Pagination:  -     Citation Subset:  -    
Copyright Information:
Copyright © 2011. Published by Elsevier Inc.
Affiliation:
Laboratory of Molecular Nutrition and Toxicology, Faculty of Pharmaceutical Sciences, Tokushima Bunri University, Yamashiro-cho, Tokushima 770-8514, Japan.
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