背景:细胞分化需要两个相反的过程的整合,稳定的细胞记忆,尤其是在转录尺度上,以及分化诱导后基因表达变异性的爆发。因此,细胞在分化过程中经历表型变化的实际能力依赖于这种平衡的改变,这种平衡有利于诱导变化的基因表达变异性。然而,没有实验数据提供了关于相同细胞的转录组在分化过程中前两次细胞分裂的规模上分歧有多快的见解。
结果:为了定量解决这个问题,我们开发了不同的实验方法来恢复相关细胞的转录组,在一次和两次分裂之后,同时在单个细胞分裂的范围内保留有关其谱系的信息。我们使用两种不同的单细胞转录组学技术(scRT-qPCR和scRNA-seq)分析了来自两个分化生物系统(人CD34细胞和T2EC鸡原代红细胞祖细胞)的相关细胞的转录组。
结论:我们发现分化姐妹细胞的基因转录谱比相同类型的非相关细胞更相似,共享相同的环境,经历相似的生物过程。更重要的是,我们观察到分化姐妹细胞之间的差异大于自我更新姐妹细胞之间的差异。此外,当比较分化的表亲细胞与自我更新的表亲细胞时,观察到这种差异从第一代到第二代逐渐增加。我们的结果有利于在分化过程中逐渐消除转录记忆。
BACKGROUND: Cell differentiation requires the integration of two opposite processes, a stabilizing cellular memory, especially at the transcriptional scale, and a burst of gene expression variability which follows the differentiation induction. Therefore, the actual capacity of a cell to undergo phenotypic change during a differentiation process relies upon a modification in this balance which favors change-inducing gene expression variability. However, there are no experimental data providing insight on how fast the transcriptomes of identical cells would diverge on the scale of the very first two cell divisions during the differentiation process.
RESULTS: In order to quantitatively address this question, we developed different experimental methods to recover the transcriptomes of related cells, after one and two divisions, while preserving the information about their lineage at the scale of a single cell division. We analyzed the transcriptomes of related cells from two differentiation biological systems (human CD34+ cells and T2EC chicken primary erythrocytic progenitors) using two different single-cell transcriptomics technologies (scRT-qPCR and scRNA-seq).
CONCLUSIONS: We identified that the gene transcription profiles of differentiating sister cells are more similar to each other than to those of non-related cells of the same type, sharing the same environment and undergoing similar biological processes. More importantly, we observed greater discrepancies between differentiating sister cells than between self-renewing sister cells. Furthermore, a progressive increase in this divergence from first generation to second generation was observed when comparing differentiating cousin cells to self renewing cousin cells. Our results are in favor of a gradual erasure of transcriptional memory during the differentiation process.