RESUMEN
Across the animal kingdom, gastrulation represents a key developmental event during which embryonic pluripotent cells diversify into lineage-specific precursors that will generate the adult organism. Here we report the transcriptional profiles of 116,312 single cells from mouse embryos collected at nine sequential time points ranging from 6.5 to 8.5 days post-fertilization. We construct a molecular map of cellular differentiation from pluripotency towards all major embryonic lineages, and explore the complex events involved in the convergence of visceral and primitive streak-derived endoderm. Furthermore, we use single-cell profiling to show that Tal1-/- chimeric embryos display defects in early mesoderm diversification, and we thus demonstrate how combining temporal and transcriptional information can illuminate gene function. Together, this comprehensive delineation of mammalian cell differentiation trajectories in vivo represents a baseline for understanding the effects of gene mutations during development, as well as a roadmap for the optimization of in vitro differentiation protocols for regenerative medicine.
Asunto(s)
Diferenciación Celular/genética , Embrión de Mamíferos/citología , Embrión de Mamíferos/metabolismo , Gastrulación , Organogénesis , Análisis de la Célula Individual , Animales , Linaje de la Célula/genética , Quimera/embriología , Quimera/genética , Quimera/metabolismo , Endodermo/citología , Endodermo/embriología , Endodermo/metabolismo , Endotelio/citología , Endotelio/embriología , Endotelio/metabolismo , Femenino , Gastrulación/genética , Perfilación de la Expresión Génica , Regulación del Desarrollo de la Expresión Génica/genética , Hematopoyesis/genética , Masculino , Mesodermo/citología , Mesodermo/embriología , Ratones , Mutación/genética , Células Mieloides/citología , Organogénesis/genética , Células Madre Pluripotentes/citología , Células Madre Pluripotentes/metabolismo , Línea Primitiva/citología , Línea Primitiva/embriología , Proteína 1 de la Leucemia Linfocítica T Aguda/deficiencia , Proteína 1 de la Leucemia Linfocítica T Aguda/genéticaRESUMEN
Chronic myeloid leukemia (CML) is associated with chromosomal translocation t(9; 22), which results in formation of the BCR-ABL oncogene. CML is treated with tyrosine kinase inhibitors (TKIs), which target BCR-ABL, to eradicate BCR-ABL + cells. However, the TKI imatinib (IM) fails to eliminate quiescent leukemia stem cells (LSCs) in CML. In this study, we demonstrate that transcription factor TAL1 is down-regulated in CML LSCs by BCR-ABL, and IM triggers TAL1 mRNA expression. In addition, loss of TAL1 abrogates IM-induced CML cell apoptosis. RNA-seq analysis suggests that TAL1 expression may affect PI3K/AKT pathway. Moreover, depletion of TAL1 inhibits the expression of PTEN, which is a negative regulator of the PI3K/AKT pathway. Our results reveal an unexpected involvement of TAL1 in CML etiology and demonstrate that TAL1 may regulate PTEN expression and lead to inhibition of the PI3K/AKT pathway in the response of CML cells to TKI. These results implicate regulation of PTEN expression as a novel mechanism for the transcriptional regulatory networks of TAL1 in CML.