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Proprotein convertase PACE4 is down-regulated by the basic helix-loop-helix transcription factor hASH-1 and MASH-1
I Yoshida1, S Koide, S I Hasegawa
1Department of Biological Science and Technology, Faculty of Engineering, The University of Tokushima, 2-1 Minamijosanjima, Tokushima 770-8506, Japan.
The Biochemical Journal
|December 12, 2001
Summary
Human achaete-scute homologue 1 (hASH-1) negatively regulates PACE4 gene expression in neural development. hASH-1 binds to E-box elements, impacting TGF-beta-related protein activation during neural differentiation.
Area of Science:
- Molecular Biology
- Developmental Biology
- Neuroscience
Background:
- PACE4 is a proprotein convertase crucial for activating TGF-beta-related proteins during embryogenesis.
- The PACE4 gene's 5'-upstream region contains E-box elements, with a cluster acting as a negative regulator.
- Mammalian achaete-scute homologue 1 (MASH-1) binds E-boxes and collaborates with E47.
Purpose of the Study:
- To investigate the role of basic helix-loop-helix (bHLH) factors, specifically human achaete-scute homologue 1 (hASH-1), in regulating PACE4 gene expression during neural development.
- To identify the specific regulatory elements and binding factors involved in PACE4 gene control.
Main Methods:
- Analysis of PACE4 and hASH-1 expression in neuroblastoma cell lines.
- Overexpression studies of hASH-1 and other bHLH factors.
- Luciferase reporter assays to assess promoter activity.
- Gel mobility-shift assays to confirm protein-DNA binding.
Main Results:
- PACE4 and hASH-1 expression showed an inverse correlation in neuroblastoma cell lines.
- Overexpression of hASH-1 or MASH-1 significantly decreased endogenous PACE4 expression, but not other convertases.
- Other neural bHLH factors did not affect PACE4 expression.
- An E-box cluster functioned as a negative regulatory element for PACE4 promoter activity in hASH-1-expressing cells.
- hASH-1 binding to the E-box cluster was confirmed.
Conclusions:
- PACE4 is identified as a direct target gene of hASH-1, a key factor in initiating neural differentiation.
- hASH-1-mediated alteration of PACE4 expression influences the biological activities of TGF-beta-related proteins through post-translational modification.