Only the site in the ERSE motif in the ALG12 promoter, selleck chemical however, are crucial to the responsive ness to Tg as well as the CRELD2 promoter. Finally, we measured the pro moter activity of the entire intergenic region of the CRELD2 ALG12 gene pair in the both direction after Tg treatment or ATF6 cotransfection. Both promoter constructs only slightly responded to Tg, but the deletion of the three suppressive regions restored respon siveness to Tg. Furthermore, the basal promoter activ ities of these mutant constructs markedly decreased. ATF6 overexpression enhanced the promo ter activity of all of the above mentioned constructs. The Tg responsive reporter constructs also showed a further increase in their promoter activities by ATF6 overexpression.

Recently, we identified CRELD2 as a novel ER stress inducible gene and characterized its ATF6 dependent transcriptional regulation using constructs containing the proximal region of the mouse CRELD2 promoter. Genomic analyses reveal that the ALG12 gene is adjacent to the CRELD2 gene in a head to head config uration on the chromosome in some species. CRELD2 and ALG12 genes are a bidirectional gene pair arranged less than 400 bp apart. The nucleotide sequences of this intergenic region are moderately conserved among the mouse, rat and human genes. Furthermore, those regions around an ERSE motif in the CRELD2 ALG12 gene pair are highly conserved. In this study, we demon strate that the expression of CRELD2 and ALG12 mRNAs, and GRP78 and GADD153 mRNAs, which are well known ER stress inducible genes, was induced by three distinct ER stress inducers.

In regards to the promoter activity of the mouse CRELD2 ALG12 gene pair, only the CRELD2 promoter containing just the proximal region significantly responded to Tg. Additionally, the CRELD2 promoter containing Carfilzomib the full intergenic region decreased in responsive ness to Tg, whereas its basal promoter activity markedly increased. In contrast, the ALG12 promoters only slightly responded to Tg even though some of the reporters con tained the ERSE motif, which is 300 bp apart from the transcription start site of the mouse ALG12 gene. The direction of the ERSE motif and its distance from each of the transcription start sites for the mouse CRELD2 or ALG12 genes, however, appear to have no influence in these findings. Therefore, it seems that the full intergenic region contains one or more unknown suppressive sites that interfere with the ERSE mediating enhancement of the ALG12 and CRELD2 promoter activities. Reporter constructs used in this study contain 5 untranslated regions of CRELD2 and or ALG12 gene. Especially, reporter constructs containing the entire intergenic region of CRELD2 ALG12 gene pair contain the UTR regions at both ends.