BACKGROUND Reversible ε-amino acetylation of lysine residues regulates transcription as well as metabolic flux; however, roles for specific lysine acetyltransferases in skeletal muscle physiology and function are unknown. In this study, we investigated the role of the related acetyltransferases p300 and cAMP response element-binding protein-binding protein (CBP) in skeletal muscle transcriptional homeostasis and physiology in adult mice. METHODS Mice with skeletal muscle-specific and inducible knockout of p300 and CBP (PCKO) were generated by crossing mice with a tamoxifen-inducible Cre recombinase expressed under the human α-skeletal actin promoter with mice having LoxP sites flanking exon 9 of the Ep300 and Crebbp genes. Knockout of PCKO was induced at 13-15 weeks of age via oral gavage of tamoxifen for 5 days to both PCKO and littermate control [wildtype (WT)] mice. Body composition, food intake, and muscle function were assessed on day 0 (D0) through 5 (D5). Microarray and tandem mass tag mass spectrometry analyses were performed to assess global RNA and protein levels in skeletal muscle of PCKO and WT mice. RESULTS At D5 after initiating tamoxifen treatment, there was a reduction in body weight (-15%), food intake (-78%), stride length (-46%), and grip strength (-45%) in PCKO compared with WT mice. Additionally, ex vivo contractile function [tetanic tension (kPa)] was severely impaired in PCKO vs. WT mice at D3 (~70-80% lower) and D5 (~80-95% lower) and resulted in lethality within 1 week-a phenotype that is reversed by the presence of a single allele of either p300 or CBP. The impaired muscle function in PCKO mice was paralleled by substantial transcriptional alterations (3310 genes; false discovery rate < 0.1), especially in gene networks central to muscle contraction and structural integrity. This transcriptional uncoupling was accompanied by changes in protein expression patterns indicative of impaired muscle function, albeit to a smaller magnitude (446 proteins; fold-change > 1.25; false discovery rate < 0.1). CONCLUSIONS These data reveal that p300 and CBP are required for the control and maintenance of contractile function and transcriptional homeostasis in skeletal muscle and, ultimately, organism survival. By extension, modulating p300/CBP function may hold promise for the treatment of disorders characterized by impaired contractile function in humans.

中文翻译：

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p300 和 cAMP 反应元件结合蛋白结合蛋白在骨骼肌稳态、收缩功能和存活中的作用。

背景赖氨酸残基的可逆ε-氨基乙酰化调节转录以及代谢通量；然而，特定赖氨酸乙酰转移酶在骨骼肌生理学和功能中的作用尚不清楚。在这项研究中，我们调查了相关乙酰转移酶 p300 和 cAMP 反应元件结合蛋白结合蛋白 (CBP) 在成年小鼠骨骼肌转录稳态和生理学中的作用。方法 骨骼肌特异性和诱导型 p300 和 CBP (PCKO) 敲除小鼠是通过将小鼠与在人 α-骨骼肌肌动蛋白启动子下表达的他莫昔芬诱导型 Cre 重组酶与具有位于 Ep300 和外显子 9 侧翼的 LoxP 位点的小鼠杂交而产生的。克雷布基因。在 13-15 周龄时通过对 PCKO 和同窝对照 [野生型 (WT)] 小鼠口服他莫昔芬 5 天诱导 PCKO 基因敲除。在第 0 天 (D0) 至第 5 天 (D5) 评估身体成分、食物摄入量和肌肉功能。进行微阵列和串联质量标签质谱分析以评估 PCKO 和 WT 小鼠骨骼肌中的整体 RNA 和蛋白质水平。结果 在开始他莫昔芬治疗后的第 5 天，与 WT 相比，PCKO 的体重 (-15%)、食物摄入量 (-78%)、步幅 (-46%) 和握力 (-45%) 减少老鼠。此外，与 PCKO 相比，体外收缩功能 [强直张力 (kPa)] 严重受损。WT 小鼠在第 3 天（降低约 70-80%）和第 5 天（降低约 80-95%）并在 1 周内导致致死率 - 这种表型因 p300 或 CBP 的单个等位基因的存在而逆转。PCKO 小鼠肌肉功能受损与大量转录改变（3310 个基因；错误发现率 < 0.1）并行，尤其是在对肌肉收缩和结构完整性至关重要的基因网络中。这种转录解偶联伴随着表明肌肉功能受损的蛋白质表达模式的变化，尽管幅度较小（446 个蛋白质；倍数变化 > 1.25；错误发现率 < 0.1）。结论 这些数据表明 p300 和 CBP 是控制和维持骨骼肌收缩功能和转录稳态以及最终生物体存活所必需的。引申开来，