In:
The FEBS Journal, Wiley, Vol. 281, No. 22 ( 2014-11), p. 5132-5146
Abstract:
X‐box binding protein 1 ( XBP 1), a transcription factor of the unfolded protein response, plays various roles in many biological processes. We examined its pro‐adipogenic activity and target genes during adipogenic differentiation in wild‐type and genetically modified 3T3‐L1 cells. Signalling pathways that contribute to Xbp1 m RNA splicing, and the correlation of the transcriptionally active XBP1 isoform (XBP1s) level with body mass index and the level of peroxisome proliferator‐activated receptor γ2 (PPARγ2) in human adipose tissues were also examined. The m RNA and nuclear protein expression levels of XBP1s increased immediately following hormonal induction of adipogenesis, reaching a peak at 6 h. Results from c DNA microarray and gene expression analyses using genetically modified cells indicated that PPARγ2 was a principal target of XBP1s. The XBP1s‐specific binding motif, which is distinct from the CCAAT /enhancer‐binding protein α binding site, was identified in the PPARγ2 promoter by site‐directed mutagenesis. Fetal bovine serum, insulin, 3‐isobutyl‐1‐methylxanthine and dexamethasone contributed independently to Xbp1 m RNA splicing. In human subcutaneous adipose tissues, the levels of both Xbp1s and Ppar γ 2 m RNA increased proportionally with body mass index, and there was a significant positive correlation between the two genes. These data suggest for the first time that positive regulation of PPARγ2 is a principal mechanism of XBP1s‐mediated adipogenesis in 3T3‐L1 cells.
Type of Medium:
Online Resource
ISSN:
1742-464X
,
1742-4658
DOI:
10.1111/febs.2014.281.issue-22
Language:
English
Publisher:
Wiley
Publication Date:
2014
detail.hit.zdb_id:
2172518-4
SSG:
12
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