Shaban Kholoud, Sauty Safia Mahabub, Yankulov Krassimir
Department of Molecular and Cellular Biology, University of Guelph, Guelph, ON, Canada.
Front Genet. 2021 Mar 4;12:630506. doi: 10.3389/fgene.2021.630506. eCollection 2021.
Phenotypic heterogeneity provides growth advantages for a population upon changes of the environment. In , such heterogeneity has been observed as "on/off" states in the expression of individual genes in individual cells. These variations can persist for a limited or extended number of mitotic divisions. Such traits are known to be mediated by heritable chromatin structures, by the mitotic transmission of transcription factors involved in gene regulatory circuits or by the cytoplasmic partition of prions or other unstructured proteins. The significance of such epigenetic diversity is obvious, however, we have limited insight into the mechanisms that generate it. In this review, we summarize the current knowledge of epigenetically maintained heterogeneity of gene expression and point out similarities and converging points between different mechanisms. We discuss how the sharing of limiting repression or activation factors can contribute to cell-to-cell variations in gene expression and to the coordination between short- and long- term epigenetic strategies. Finally, we discuss the implications of such variations and strategies in adaptation and aging.
表型异质性使种群在环境变化时具备生长优势。在[具体情况未提及]中，这种异质性表现为单个细胞中单个基因表达的“开/关”状态。这些变异能在有限或延长的有丝分裂次数中持续存在。已知此类性状由可遗传的染色质结构、参与基因调控回路的转录因子的有丝分裂传递，或由朊病毒或其他无结构蛋白的细胞质分配介导。然而，这种表观遗传多样性的意义虽显而易见，但我们对其产生机制的了解有限。在本综述中，我们总结了目前关于基因表达表观遗传维持异质性的知识，并指出不同机制之间的相似性和交汇点。我们讨论了有限的抑制或激活因子的共享如何导致基因表达的细胞间差异以及短期和长期表观遗传策略之间的协调。最后，我们讨论了此类变异和策略在适应与衰老方面的意义。
