产肉量是家畜（包括猪、牛和羊等）重要生产力指标和经济性状之一。产肉量是典型的数量性状，受多基因调控。影响产肉性状形成的基础是骨骼肌组织的生长和发育。骨骼肌生长发育是一个复杂的生物学过程，包括成肌细胞的形成、增殖、凋亡、迁移、融合和分化。骨骼肌损伤修复过程中基因表达变化与初始胚胎发育过程类似，完美的重现了上述骨骼肌生长发育过程。因此，骨骼肌损伤修复被认为是研究骨骼肌生长发育的理想模型。鉴定骨骼肌损伤修复过程中调节肌生成相关重要基因和特定调控网络，能够为家畜产肉量等重要经济生产性状形成的分子机制提供理论支持。已有研究表明，骨骼肌功能障碍与肌营养不良、萎缩，2型糖尿病和衰老相关的肌肉减少症等500多种人类疾病密切相关。因此，深入了解骨骼肌损伤修复过程中基因表达差异以及调控网络，也能为再生医学提供新的药物靶点，这些靶点可以增强或诱导功能性骨骼肌从头生成，以治疗先天性缺失或创伤性组织损失。

近些年针对小鼠骨骼肌损伤修复的单细胞RNA 测序(scRNA-seq)陆续产出了大量数据，但是，从单细胞水平研究骨骼肌再生过程中基因表达变化的数据库尚未构建。本研究汇集了七个关键再生时间点和正常骨骼肌单细胞RNA-seq数据（共计超过 105,000 个细胞）开展一系列生物信息分析，包括细胞聚类、细胞类型注释、细胞周期识别、骨骼肌卫星细胞发育状态转换轨迹和调节单元动态表达图谱构建等。开发构建了SCSMRD （https://scsmrd.fengs-lab.com）数据库，界面友好，操作简单，提供了多种搜索功能，包括，用户感兴趣基因在不同细胞类型和损伤修复不同时间点的动态表达图谱，不同细胞类型中特异调节单元网络动态变化和用户感兴趣基因基因在骨骼肌卫星细胞发育状态转变过程中的表达模式等。SCSMRD数据库为研究人员在单细胞层面研究骨骼肌损伤修复的转录组动态变化提供了可靠的生信技术支撑和数据支持。

Type A spermatogonial stem cells are the only immortal diploid cells in the postnatal animal that undergo self-renewal through the lifetime of an animal and transmit genes to subsequent generations. In this paper, the generation and characterization of double-transgenic mice co-expressing the Escherichia coli appA gene and human MxA gene generated via the in vivo transfection of type A spermatogonial cells were reported for the first time. The dicistronic expression vector pcDNA-appA-MxA(AMP) and ExGen500 transfection reagent were injected into the testicular tissue of 7-d-old male ICR mice. The mice that underwent testismediated gene transfer were mated with wild-type female mice, and the integration and expression of the foreign genes in the offspring were evaluated. Transgenic mice that co-expressed appA and MxA showed a gene integration rate of 8.89% (16/180). The transgenic mice were environmentally friendly, as the amount of phosphorous remaining in the manure was reduced by as much as 11.1% by the appA gene (P<0.05); these animals also exhibited a strong anti-viral phenotype.