Project description:Human limbs emerge during the fourth post-conception week as mesenchymal buds, which develop into fully formed limbs over the subsequent months. This process is orchestrated by numerous temporally and spatially restricted gene expression programmes, making congenital alterations in phenotype common. Decades of work with model organisms have defined the fundamental mechanisms underlying vertebrate limb development, but an in-depth characterization of this process in humans has yet to be performed. Here we detail human embryonic limb development across space and time using single-cell and spatial transcriptomics. We demonstrate extensive diversification of cells from a few multipotent progenitors to myriad differentiated cell states, including several novel cell populations. We uncover two waves of human muscle development, each characterized by different cell states regulated by separate gene expression programmes, and identify musculin (MSC) as a key transcriptional repressor maintaining muscle stem cell identity. Through assembly of multiple anatomically continuous spatial transcriptomic samples using VisiumStitcher, we map cells across a sagittal section of a whole fetal hindlimb. We reveal a clear anatomical segregation between genes linked to brachydactyly and polysyndactyly, and uncover transcriptionally and spatially distinct populations of the mesenchyme in the autopod. Finally, we perform single-cell RNA sequencing on mouse embryonic limbs to facilitate cross-species developmental comparison, finding substantial homology between the two species.
Project description:To investigate into the evolutionary conversation of the single-cell transcriptome of human fetal limbs, especially the principles of forelimb and hindlimb specification and proximal-distal axis establishment, we collected the forelimbs and hindlimbs of mouse embryos matching human samples. We dissected the limbs to separate proximal, middle and distal parts and generated single-cell RNA-seq data of more than 70,000 cells. Combining this dataset with our human data, we are able to see highly conserved limb cell types and limb axis drivers.
Project description:We performed spatial transcriptomic experiments using the 10x Visium assay, generating high-quality transcriptomic profiles for samples from PCW5 to PCW8
Project description:By using single cell RNA-seq,We dissect the cellular heterogeneity and transcriptome profiles during limb development, and reveal the characteristic features of limb development and musculoskeletal stem/progenitor cell populations involved in limb lineage development. Our study therefore systematically decoded molecular markers and cellular program of limb development that would shed lights on limb developmental biology.
Project description:Proper development of limb bud relies on the concordance of various signals, otherwise limb deformities occur. We report that heterogeneous nuclear ribonucleoprotein K (hnRNPK) is essential for limb bud development. here, we knock out Hnrnpk in limb bud and exert the RNA-seq, ATAC-seq, CUT&RUN-seq, and Hi-C assay using primary limb bud cells to explore the function of Hnrnpk in limb bud development.
Project description:We report here high-throughput RNA sequencing (RNA-seq) to characterise the transcriptional landscape of the embryonic chicken Müllerian duct during development.
Project description:Detailed information about stage-specific changes in gene expression is crucial for understanding the gene regulatory networks underlying development and the various signal transduction pathways contributing to morphogenesis. Here, we describe the global gene expression dynamics during early murine limb development, when cartilage, tendons, muscle, joints, vasculature, and nerves are specified and the musculoskeletal system of the limbs is established. We used whole-genome microarrays to identify genes with differential expression at 5 stages of limb development (E9.5 to 13.5), during fore-limb and hind-limb patterning. We found that the onset of limb formation is characterized by an up-regulation of transcription factors, which is followed by a massive activation of genes during E10.5 and E11.5 which tampers off at later time points. Among 3520 genes identified as significantly up-regulated in the limb, we find ~30% to be novel, dramatically expanding the repertoire of candidate genes likely to function in the limb. Hierarchical and stage-specific clustering identified expression profiles that correlate with functional programs during limb development and are likely to provide new insights into specific tissue patterning processes. Here we provide for the first time, a comprehensve analysis of developmentally regulated genes during murine limb development, and provide some novel insights into the expression dynamics governing limb morphogenesis. Fifty- one arrays were analyzed, consisting of whole fore-limb and hind-limb bud RNA (experimental) and whole embryo RNA (reference) samples from E9.5 to E13.5 DPC mouse (FVB strain). Embryos were not pooled to generate samples. Each time point has 3 to 5 biological replicates for limb bud samples, duplicates for whole embryos. Comparisons were made between limb bud samples and whole embryo at the same stage, fore-limb samples of different stages, hind-limb samples of different stages, and fore-limb samples compared to hind-limb samples at the same or the next stage.