Alternate PAX3 and PAX7 C-terminal isoforms in myogenic differentiation and sarcomagenesis
Alternate PAX3 and PAX7 C-terminal isoforms in myogenic differentiation and sarcomagenesis
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DOI：
10.1007/s12094-011-0640-y
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发表时间：
2011-03-01
影响因子：
3.4
通讯作者：
Ziman, Mel
中科院分区：
文献类型：
--
作者：
Charytonowicz, Elizabeth;Matushansky, Igor;Ziman, Mel
Pax3 和 Pax7 是密切相关的基因，参与骨骼肌发育和再生过程中细胞向肌源性谱系的定向。多个 Pax3 和 Pax7 转录本由基因表达，产生具有潜在不同 DNA 结合和反式激活特性的不同亚型。本研究的目的是研究 Pax3 和 Pax7 C 端亚型在肌源性分化和肿瘤发生过程中的影响，因为涉及这些基因的融合通常与肺泡横纹肌肉瘤 (ARMS) 相关。用 PAX3/FKHR 稳定转染未定型（小鼠间充质干细胞，MSC）和定型 (C2C12) 肌原性前体细胞 和PAXC7/FKHR融合基因。我们分析了新产生的细胞与亲本细胞的基因和蛋白质表达，以确定 Pax3 和 Pax7 C 端亚型的功能重要性。我们发现转录本 Pax3c 在未分化的 C2C12 和 MSC 细胞中低水平表达，但其表达水平在分化后期显着增加。然而，Pax3d 转录物的表达水平在分化后仅略有增加。 Pax7 转录物在分化前存在于定型 C2C12 细胞中，但在未定型 MSC 中不存在，在分化后的 MSC 中显着增加。我们还发现 PAX/FKHR 融合体的存在阻止了 C2C12 和 MSC 细胞的终末肌原性分化，并增加了离散内源性 Pax3/7 转录物的表达，特别是 Pax3d 和 Pax7B。结论 我们的结果表明，Pax3 和 Pax7 转录物都是细胞向肌源性谱系定型所必需的，每种转录物都具有不同的作用。更具体地，Pax3c亚型可能是终末肌原性分化所必需的，而Pax3d亚型可能涉及未分化细胞的维持和/或增殖。
Pax3 and Pax7 are closely related genes that are involved in commitment of cells to a myogenic lineage during skeletal muscle development and regeneration. Several Pax3 and Pax7 transcripts are expressed from the genes, generating different isoforms with potentially distinct DNA binding and transactivation properties. The aim of this study was to investigate the implication of Pax3 and Pax7 C-terminal isoforms during myogenic differentiation and tumorigenesis, since fusions involving these genes are commonly associated with alveolar rhabdomyosarcoma (ARMS).Uncommitted (mouse mesenchymal stem cells, MSCs) and committed (C2C12) myogenic precursor cells were stably transfected with PAX3/FKHR and PAXC7/FKHR fusion genes. We analysed gene and protein expression comparing the newly generated cells with the parental cells, to determine the functional importance of Pax3 and Pax7 C-terminal isoforms.We found that the transcript Pax3c was expressed at low levels in undifferentiated C2C12 and MSCs cells, but its expression levels increased considerably at later stages of differentiation. However, expression levels of Pax3d transcript increased only slightly after differentiation. Pax7 transcripts, present before differentiation in committed C2C12 cells, but absent in uncommitted MSCs, increased noticeably in MSCs after differentiation. We also found that the presence of PAX/FKHR fusions prevented both C2C12 and MSC cells from terminal myogenic differentiation and increased the expression of discrete endogenous Pax3/7 transcripts, in particular Pax3d and Pax7B. Conclusions Our results suggest that both Pax3 and Pax7 transcripts are required for commitment of cells to the myogenic lineage, with each transcript having a distinct role. More specifically, the Pax3c isoform may be required for terminal myogenic differentiation whereas the Pax3d isoform may be involved in undifferentiated cell maintenance and/or proliferation.