Wnt3a signal pathways activate MyoD expression by targeting cis-elements inside and outside its distal enhancer
| Autor: | Yi Ju Wu, Hsuan Chia Chang, Yu Chih Pan, Xiao Wen Wang, Shen Liang Chen, Han Feng Teng |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2015 |
| Předmět: |
muscle
PAX3 lcsh:Life lcsh:QR1-502 SKM skeletal muscle MyoD Biochemistry PBST PBS containing 0.5% Tween 20 lcsh:Microbiology CMB confluent myoblast P6P proximal 6 kb promoter Myotome DE distal enhancer Paired Box Transcription Factors Wnt Signaling Pathway PRR proximal regulatory region Genetics qRT-PCR quantitative reverse transcription–PCR DMEM Dulbecco's modified Eagle's medium TRE T3-response element Myogenesis Wnt signaling pathway PAX7 Transcription Factor HRP horseradish peroxidase Wnt3a Fgf fibroblast growth factor dpc day(s) postcoitum musculoskeletal system Cell biology medicine.anatomical_structure JNK c-Jun N-terminal kinase embryonic structures MYF5 Myogenic Regulatory Factor 5 myogenesis WRE Wnt-response element animal structures Biophysics T3 3 3′ 5-tri-iodothyronine Gapdh glyceraldehyde-3-phosphate dehydrogenase Biology Response Elements Cell Line HEK human embryonic kidney GSK3β glycogen synthase kinase 3β Wnt3A Protein Shh Sonic Hedgehog medicine Humans MRF myogenic regulatory factor Molecular Biology PAX3 Transcription Factor MyoD Protein Original Paper LEF lymphoid enhancer factor HEK 293 cells Cell Biology β-catenin Pax7 NFAT nuclear factor of activated T-cells lcsh:QH501-531 DRR distal regulatory region TKE thymidine kinase promoter and enhancer Gene Expression Regulation MT myotube Myogenic regulatory factors BAC bacterial artificial chromosome MAPK mitogen-activated protein kinase |
| Zdroj: | Bioscience Reports, Vol 35, Iss 2, p e00180 (2015) Bioscience Reports |
| ISSN: | 1573-4935 |
| Popis: | Wnt proteins are secreted cytokines and several Wnts are expressed in the developing somites and surrounding tissues. Without proper Wnt stimulation, the organization of the dermomyotome and myotome can become defective. These Wnt signals received by somitic cells can lead to activation of Pax3/Pax7 and myogenic regulatory factors (MRFs), especially Myf5 and MyoD. However, it is currently unknown whether Wnts activate Myf5 and MyoD through direct targeting of their cis-regulatory elements or via indirect pathways. To clarify this issue, in the present study, we tested the regulation of MyoD cis-regulatory elements by Wnt3a secreted from human embryonic kidney (HEK)-293T cells. We found that Wnt3a activated the MyoD proximal 6.0k promoter (P6P) only marginally, but highly enhanced the activity of the composite P6P plus distal enhancer (DE) reporter through canonical and non-canonical pathways. Further screening of the intervening fragments between the DE and the P6P identified a strong Wnt-response element (WRE) in the upstream −8 to −9k region (L fragment) that acted independently of the DE, but was dependent on the P6P. Deletion of a Pax3/Pax7-targeted site in the L fragment significantly reduced its response to Wnt3a, implying that Wnt3a activates the L fragment partially through Pax3/Pax7 action. Binding of β-catenin and Pax7 to their target sites in the DE and the L fragment respectively was also demonstrated by ChIP. These observations demonstrated the first time that Wnt3a can directly activate MyoD expression through targeting cis-elements in the DE and the L fragment. We found that Wnt3a can directly activate MyoD expression through targeting cis-elements in the distal enhancer and in the upstream −8 to −9k region. A novel Pax3/Pax7-involved pathway and both canonical and non-canonical Wnt pathways are involved in this activation. |
| Databáze: | OpenAIRE |
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