Single-cell analysis reveals lineage segregation in early post-implantation mouse embryosThe mammalian post-implantation embryo has been extensively investigated at the tissue level. However, to unravel the molecular basis for the cell-fate plasticity and determination, it is essential to study the characteristics of individual cells. In particular, the individual definitive endoderm (DE) cells have not been characterized in vivo. Here, we report gene expression patterns in single cells freshly isolated from mouse embryos on days 5.5 and 6.5. Initial transcriptome data from 124 single cells yielded signature genes for the epiblast, visceral endoderm, and extra-embryonic ectoderm and revealed a unique distribution pattern of fibroblast growth factor (FGF) ligands and receptors.
Serine/Threonine Kinase 40 (Stk40) Functions as a Novel Regulator of Skeletal Muscle DifferentiationSkeletal muscle differentiation is a precisely coordinated process, and the molecular mechanism regulating the process remains incompletely understood. Here we report the identification of serine/threonine kinase 40 (Stk40) as a novel positive regulator of skeletal myoblast differentiation in culture and fetal skeletal muscle formation in vivo. We show that the expression level of Stk40 increases during skeletal muscle differentiation. Down-regulation and overexpression of Stk40 significantly decreases and increases myogenic differentiation of C2C12 myoblasts, respectively.