mRNP granule proteins Fmrp and Dcp1a differentially regulate mRNP complexes to contribute to control of muscle stem cell quiescence and activation.
mRNP granule proteins Fmrp and Dcp1a differentially regulate mRNP complexes to contribute to control of muscle stem cell quiescence and activation.
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DOI：
10.1186/s13395-021-00270-9
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发表时间：
2021-07-08
期刊：
影响因子：
4.9
通讯作者：
Dhawan J
中科院分区：
文献类型：
--
作者：
Roy N;Sundar S;Pillai M;Patell-Socha F;Ganesh S;Aloysius A;Rumman M;Gala H;Hughes SM;Zammit PS;Dhawan J
在骨骼肌再生过程中，卫星干细胞使用不同的途径来修复受损的肌纤维或通过恢复静止来自我更新。细胞/有丝分裂静止采用促进平衡或启动状态的机制，包括改变的RNA周转和翻译抑制。在这里，我们调查的mRNP颗粒蛋白脆性X智力迟钝蛋白（Fmrp）和去帽蛋白1a（Dcp 1a）在肌肉干细胞的静止和分化的作用。使用成年小鼠分离的单个肌纤维，我们建立了肌肉干细胞与肌纤维中包括Fmrp和Dcp 1a的mRNP颗粒蛋白的差异富集。我们研究了成年Fmr 1-/-小鼠的肌肉组织稳态，分析了体内肌纤维横截面积和离体卫星细胞增殖。我们在C2 C12培养模型中探讨了Dcp 1a和Fmrp在静止、增殖和分化中的分子机制。在这里，我们使用多核糖体分析，成像和RNA/蛋白质表达分析，以建立在不同的细胞状态的mRNP颗粒蛋白的丰度和装配状态，以及敲除细胞的表型。静止肌卫星细胞富含含有翻译抑制因子Fmrp的斑点，但不含mRNA衰变因子Dcp 1a。从Fmr 1-/-小鼠分离的MuSC表现出增殖缺陷，成熟肌纤维显示横截面积减少，表明Fmrp在肌肉稳态中的作用。Fmrp和Dcp 1a的表达和组织在肌纤维上的初级MuSC激活期间变化，其中Fmrp斑点在静止时突出，但Dcp 1a斑点在激活/增殖期间出现。这种相互表达的Fmrp和Dcp 1a斑点是重演C2 C12文化模型的静止和激活：与其作为翻译抑制剂的作用一致，Fmrp是丰富的非翻译mRNP复合物在静止成肌细胞丰富; Dcp 1a斑点在静止中丢失，这表明稳定和抑制的成绩单。在增殖过程中，每种蛋白质的功能不同;而Fmrp敲低导致增殖降低和细胞周期蛋白表达降低，Dcp 1a敲低导致细胞增殖增加和细胞周期蛋白表达升高。然而，敲低Fmrp或Dcp 1a导致受损的分化。我们还观察到交叉调节的衰减与存储mRNP颗粒;敲低Fmrp增强积累的Dcp 1a斑点，而敲低Dcp 1a导致增加Fmrp斑点。综上所述，我们的研究结果提供了证据，mRNA周转与利用的平衡是特定的不同的细胞状态。在线版本包含补充材料，可通过10.1186/s13395-021-00270-9获得。
During skeletal muscle regeneration, satellite stem cells use distinct pathways to repair damaged myofibers or to self-renew by returning to quiescence. Cellular/mitotic quiescence employs mechanisms that promote a poised or primed state, including altered RNA turnover and translational repression. Here, we investigate the role of mRNP granule proteins Fragile X Mental Retardation Protein (Fmrp) and Decapping protein 1a (Dcp1a) in muscle stem cell quiescence and differentiation. Using isolated single muscle fibers from adult mice, we established differential enrichment of mRNP granule proteins including Fmrp and Dcp1a in muscle stem cells vs. myofibers. We investigated muscle tissue homeostasis in adult Fmr1-/- mice, analyzing myofiber cross-sectional area in vivo and satellite cell proliferation ex vivo. We explored the molecular mechanisms of Dcp1a and Fmrp function in quiescence, proliferation and differentiation in a C2C12 culture model. Here, we used polysome profiling, imaging and RNA/protein expression analysis to establish the abundance and assembly status of mRNP granule proteins in different cellular states, and the phenotype of knockdown cells. Quiescent muscle satellite cells are enriched for puncta containing the translational repressor Fmrp, but not the mRNA decay factor Dcp1a. MuSC isolated from Fmr1-/- mice exhibit defective proliferation, and mature myofibers show reduced cross-sectional area, suggesting a role for Fmrp in muscle homeostasis. Expression and organization of Fmrp and Dcp1a varies during primary MuSC activation on myofibers, with Fmrp puncta prominent in quiescence, but Dcp1a puncta appearing during activation/proliferation. This reciprocal expression of Fmrp and Dcp1a puncta is recapitulated in a C2C12 culture model of quiescence and activation: consistent with its role as a translational repressor, Fmrp is enriched in non-translating mRNP complexes abundant in quiescent myoblasts; Dcp1a puncta are lost in quiescence, suggesting stabilized and repressed transcripts. The function of each protein differs during proliferation; whereas Fmrp knockdown led to decreased proliferation and lower cyclin expression, Dcp1a knockdown led to increased cell proliferation and higher cyclin expression. However, knockdown of either Fmrp or Dcp1a led to compromised differentiation. We also observed cross-regulation of decay versus storage mRNP granules; knockdown of Fmrp enhances accumulation of Dcp1a puncta, whereas knockdown of Dcp1a leads to increased Fmrp in puncta. Taken together, our results provide evidence that the balance of mRNA turnover versus utilization is specific for distinct cellular states. The online version contains supplementary material available at 10.1186/s13395-021-00270-9.
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影响因子：
4
作者：
Dhawan J;Laxman S
通讯作者：
Laxman S
DOI：
10.1016/j.bbagrm.2013.02.003
发表时间：
2013-06
影响因子：
4.7
作者：
Brooks, Seth A.;Blackshear, Perry J.
通讯作者：
Blackshear, Perry J.
DOI：
10.1038/nrm3591
发表时间：
2013-06
期刊：
Nature reviews. Molecular cell biology
影响因子：
--
作者：
通讯作者：
--
DOI：
10.3791/52295
发表时间：
2014-10-28
期刊：
Journal of visualized experiments : JoVE
影响因子：
--
作者：
Faye MD;Graber TE;Holcik M
通讯作者：
Holcik M
影响因子：
23.9
作者：
Crist, Colin G.;Montarras, Didier;Buckingham, Margaret
通讯作者：
Buckingham, Margaret