Truncation and mutagenesis analysis of the human X-arrestin gene promoter.

Abstract

X-arrestin (arrestin-3) is an arrestin present specifically in the outer segments of red-, green-, and blue-cone photoreceptors. The X-arrestin gene is on Xcen-q22, and consists of 17 exons with a promoter containing a TATA box and elements important for photoreceptor expression, including three CRX and one PCE-1-like element. In order to delineate the promoter structure necessary for the pan-cone-specific expression of X-arrestin, the expression of the gene in retinoblastoma cell lines was investigated, and a structure-function analysis of the promoter was conducted in the appropriate cellular substrate. Expression of X-arrestin was detected at a low level in the Y79 retinoblastoma cell line but not in the WERI retinoblastoma cell line. Truncation and expression analysis of the X-arrestin promoter in Y79 showed maximal activity in the proximal 378-bp region containing the CRX and PCE-1-like elements upstream of the TATA and CAAT boxes and a negative regulator in the distal 1-2-kbp region. Mutagenesis of the three CRX and PCE-1-like elements and expression analysis demonstrated complete elimination of the promoter activity. Mutagenesis of the TATA box and PCE-1-like element individually resulted in similar decrease in promoter activity, but the decrease in the promoter activity was greater when the CRX elements were mutagenized with a 5' to 3' spatial gradient in the negative effect, suggesting a cooperative effect of the three CRX elements. The regulation of expression from this promoter may involve the binding of a multi-protein enhanceosome complex at the CRX triplet and the PCE-1-like element, resulting in the recruitment and activation of the RNA polymerase II complex at the downstream TATA box.

• Authors: Takuro Fujimaki, Zhen-Yong Huang, Hitoshi Kitagawa, Hitoshi Sakuma, Akira Murakami, Atsushi Kanai, Margaret J McLaren, George Inana
• Journal: Gene (Gene) Vol. 339 Pg. 139-47 (Sep 15 2004) ISSN: 0378-1119 [Print] Netherlands
• PMID: 15363854 (Publication Type: Comparative Study, Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Arrestins
• Recombinant Fusion Proteins
• arrestin3
• beta-Galactosidase

Topics

• Arrestins (genetics)
• Base Sequence
• Binding Sites (genetics)
• Blotting, Northern
• Cell Line, Tumor
• Gene Expression
• Humans
• Molecular Sequence Data
• Mutagenesis
• Mutation
• Promoter Regions, Genetic (genetics)
• Recombinant Fusion Proteins (genetics)
• Retina (metabolism)
• Retinoblastoma (genetics, pathology)
• Sequence Deletion
• Transfection
• beta-Galactosidase (genetics)