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Regulation of Dp71 gene expression by Sp1 and AP2 transcription factors during neuronal differentiation
Author(s) -
Lázaro Sara Luz Morales,
Vega Bulmaro Cisneros
Publication year - 2007
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.21.5.a284-b
Subject(s) - promoter , transcription factor , downregulation and upregulation , biology , microbiology and biotechnology , gene isoform , transcription (linguistics) , gene , gene expression , regulation of gene expression , ap 1 transcription factor , genetics , linguistics , philosophy
The DMD gen has different internal promoters which regulate the expression of several isoforms called dystrophins. The dystrophin Dp71, the smallest DMD gene product, is expressed from a TATA‐less promoter localized between 62 and 63 exons of the DMD gen. Dp71 gene expression is upregulated during the neuronal diferentiation, for that reason, the aim of this work was the study of Dp71 promoter in the neuronal cell line N1E‐115. These neuronal cells can be estimulated by cAMP or DMSO to start a differentiation process. First, we observed that the leves of Dp71 mRNA was upregulated when N1E‐115 cells were stimulated to differentiation. Next, we found that the activity of the Dp71 promoter was increased in cells stimulated by cAMP. We identified the mimimal promoter region, which is located between −94 to +65 nucleotides. The minimal promoter region has four putatives sites for Sp transcription factor family and single sites for AP2 and AP1. In vitro interaction studies showed the formation of DNA‐protein complex on Sp binding sites, which are constituted by Sp1 and Sp3, and on the AP2 site, which contains the AP2alpha factor. Furthermore, we found that Dp71 promoter activity is downregulated when we introduced a mutation on the Sp sites. In contrast, when the AP2 site is mutated the promoter activity increased substantially. The overexpression of AP2alpha transcription factor resulted in downregulation of promoter activity and the overexpression of Sp1 resulted in upregulation of this activity. We have concluded that the Dp71 promoter is regulated positively by Sp1 transcription factor and that AP2 acts as a represor of its activity.