HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) All Versions of this Article: 297/2/C330    most recent 00009.2009v1 Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Google Scholar Articles by Takeo, K. Articles by Rokutan, K. PubMed PubMed Citation Articles by Takeo, K. Articles by Rokutan, K.

GROWTH, DIFFERENTIATION, AND APOPTOSIS

Oxidative stress-induced alternative splicing of transformer 2β (SFRS10) and CD44 pre-mRNAs in gastric epithelial cells

Department of Stress Science, Institute of Health Biosciences, The University of Tokushima Graduate School, Tokushima, Japan

Submitted 9 January 2009 ; accepted in final form 6 May 2009

The tra2β gene encoding an alternative splicing regulator, transformer 2-β (Tra2β), generates five alternative splice variant transcripts (tra2β1–5). Functionally active, full-length Tra2β is encoded by tra2β1 isoform. Expression and physiological significance of the other isoforms, particularly tra2β4, are not fully understood. Rat gastric mucosa constitutively expressed tra2β1 isoform and specifically generated tra2β4 isoform that includes premature termination codon-containing exon 2, when exposed to restraint and water immersion stress. Treatment of a gastric cancer cell line (AGS) with arsenite (100 µM) preferentially generated tra2β4 isoform and caused translocation of Tra2β from the nucleus to the cytoplasm in association with enhanced phosphorylation during the initial 4–6 h (acute phase). Following the acute phase, AGS cells continued upregulated tra2β1 mRNA expression, and higher amounts of Tra2β were reaccumulated in their nuclei. Treatment with small interference RNAs targeting up-frameshift-1 or transfection of a plasmid containing tra2β1 cDNA did not induce tra2β4 isoform expression and did not modify the arsenite-induced expression of this isoform, suggesting that neither the nonsense-mediated mRNA decay nor the autoregulatory control by excess amounts of Tra2β participated in the tra2β4 isoform generation. Knockdown of Tra2β facilitated skipping of the central variable region of the CD44 gene and suppressed cell growth. In contrast, overexpression of Tra2β stimulated combinatorial inclusion of multiple variable exons in the region and cell growth. The similar skipping and inclusion of the variable region were observed in arsenite-treated cells. Our results suggest that Tra2β may regulate cellular oxidative response by changing alternative splicing of distinct genes including CD44.

arsenite; splicing regulator; tra2β4 isoform; premature termination codon; cell growth