C-Myb acts as transcriptional activator of the quail PAX6 (PAX-QNR) promoter through two different mechanisms
| Autor: | S, Plaza, N, Turque, C, Dozier, M, Bailly, S, Saule |
|---|---|
| Rok vydání: | 1995 |
| Předmět: |
Homeodomain Proteins
Base Sequence PAX6 Transcription Factor Molecular Sequence Data Gene Expression Regulation Developmental Oncogenes Transfection Quail TATA Box Retina DNA-Binding Proteins Repressor Proteins Trans-Activators Animals Paired Box Transcription Factors Eye Proteins Promoter Regions Genetic In Situ Hybridization |
| Zdroj: | Oncogene. 10(2) |
| ISSN: | 0950-9232 |
| Popis: | To understand the regulation of the Pax-6 gene, which plays an important role in eye development, we have characterized the promoter region of the quail Pax-6(Pax-QNR) gene. In addition to TATA and CAAT boxes, sequence analysis revealed several putative cis-regulatory elements among which three myb-responsive elements (MRE). C-myb encodes a nuclear, DNA-binding phosphoprotein that functions as transcriptional regulator. Co-transfection in quail embryo cells of the Pax-QNR/pax-6 promoter with a vector expressing the 75 kDa c-myb protein resulted in an increase in Pax-QNR promoter activity. By footprinting experiments we identified multiple binding sites for the myb protein within the promoter region. Protein containing the myb DNA-binding domain fused to the VP16-transactivation domain was fully efficient in Pax-QNR promoter transactivation, demonstrating that myb can transactivate through a direct binding on DNA. However, a myb truncated protein devoid of DNA-binding domain was also able to transactivate the Pax-QNR promoter. These results show that this promoter can be transactivated by the myb protein directly as well as indirectly. Finally we show by in situ hybridization that c-myb is strongly expressed in the developing neuroretina, simultaneously with Pax-QNR. These observations suggest that the c-myb protein may be a regulator of Pax-QNR/pax-6. |
| Databáze: | OpenAIRE |
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