Single cell ATAC sequencing profile of a unique mesenchymal progenitor subset from the developing murine forelimb
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ABSTRACT: During mouse embryonic development, the limbs emanate from primordial buds of lateral plate mesoderm as proliferating mesenchymal cells cause protrusions of the overlying ectoderm. As the bud expands, several populations of cells are thought to migrate into the emerging limb and contribute to various specialized structures therein. A unique subset has been identified among the migrating populations that contributes to enduring stromal compartments in various tissues and is responsible for aspects of secondary morphogenesis including the formation of entheses throughout the limb. Using a lineage tracing tool, this population was sampled at various stages along the developmental continuum and chromatin accessibility was profiled at the single cell level to determine the fate and function of this cell subtype and the epigenetic programs involved.
Project description:During mouse embryonic development, the limbs emanate from primordial buds of lateral plate mesoderm as proliferating mesenchymal cells cause protrusions of the overlying ectoderm. As the bud expands, several populations of cells are thought to migrate into the emerging limb and contribute to various specialized structures therein. A unique subset has been identified among the migrating populations that contributes to enduring stromal compartments in various tissues and is responsible for aspects of secondary morphogenesis including the formation of entheses throughout the limb. Using a lineage tracing tool, this population was sampled at various stages along the developmental continuum and gene expression was profiled at the single cell level to determine the fate and function of this cell subtype and the genetic programs involved.
Project description:During mouse embryonic development, as the limb bud expands, several populations of cells are thought to migrate into the emerging limb and contribute to various specialized structures therein. A unique subset has been identified among the migrating populations that contributes to enduring stromal compartments in various tissues. Using a lineage tracing tool, this population was sampled from limb muscle after post-natal development was complete and gene expression was profiled at the single cell level to determine the fate and function of this cell subtype and the genetic programs involved.
Project description:The apical ectodermal ridge (AER) is a transient ectodermal population of cells that defines the dorso-ventral border of the developing limb bud. It functions as a major signaling centre that, through the secretion of various growth factors including FGF8, instructs the growth and patterning of the developing limb. We have identified that the AER expresses markers of cellular senescence and wanted to examine if there was any overlap with oncogene-induced senescence, an adult form of senescence induced in premalignant lesions. To achieve this, we microdissected the AER from embryonic day 11.5 mouse embryos. In addition, we collected the surface ectoderm from the proximal limb bud, that was not senescent and profiled both populations, to identify those genes that are enriched in the AER The AER was microdissected from embryonic day 11.5 mouse forelimb. Surface ectoderm from the posterior limb was used as a comparative control. Samples from 2-3 mice were pooled for each replicate, for 3-4 replicates.
Project description:The apical ectodermal ridge (AER) is a transient ectodermal population of cells that defines the dorso-ventral border of the developing limb bud. It functions as a major signaling centre that, through the secretion of various growth factors including FGF8, instructs the growth and patterning of the developing limb. We have identified that the AER expresses markers of cellular senescence and wanted to examine if there was any overlap with oncogene-induced senescence, an adult form of senescence induced in premalignant lesions. To achieve this, we microdissected the AER from embryonic day 11.5 mouse embryos. In addition, we collected the surface ectoderm from the proximal limb bud, that was not senescent and profiled both populations, to identify those genes that are enriched in the AER
Project description:Numerous studies have established a critical role for BMP signaling in skeletal development. In the developing axial skeleton, sequential SHH and BMP signals are required for specification of a chondrogenic fate in somitic tissue. A similar paradigm is thought to operate in the limb, but the signals involved are unclear. To investigate the nature of these signals we examined BMP action in mesenchymal populations derived from the early murine limb bud (~ E10.5). These populations exhibited a graded response to BMPs, in which early limb mesenchymal (EL) cells (from the distal hind limb) displayed an anti-chondrogenic response, whereas BMPs promoted chondrogenesis in older cell populations. To better understand the molecular basis of disparate BMP action in these various populations, gene expression profiling with Affymetrix microarrays was employed to identify BMP-regulated genes. These analyses showed that BMPs induced a distinct gene expression pattern in the EL cultures versus later mesenchymal limb populations (IM and LT). Mouse embryos at gestational age E10.5 were collected and various portions of the limb were micro-dissected. These led to the generation of three populations of cells, early (EL) limb mesenchymal cells from the distal half of the hind limb, an intermediate (IM) population derived from the distal 1/3 of the fore limb, and a later (LT) population from the proximal 2/3 of the fore limb. Mesenchymal cells were isolated and cultured with and without BMP4 treatment. RNA was extracted from cultures at either Day 0,1 or 2, labelled and hybridized to Affymetrix 430 2.0 microarrays. For each time point, RNA was collected from two biological replicates for each treatment condition.
Project description:Purpose: The response to Hedgehog signaling in the limb is driven by GLI bound enhancers and the majority of Hh targets in the developing limb bud are regulated solely by the activity of GLI-repressor. Currently we do not have a comprehensive understanding of how GLI bound enhancers respond Hedgehog signaling. The goal of this study is to identify how GLI bound enhancers are regulated by Hedgehog signaling and specifically by GLI-repressor. Methods: ChIP-seq was performed in Embryonic day 10.5 mouse limb buds from mice with endogenously FLAG tagged Gli3. Results: We identified 7282 GLI3 binding regions in the E10.5 limb bud.
Project description:To investigate the effect of the mesenchymal quiescence regulator, Hic1, on forelimb development, we collected forelimbs from conventional Hic1 knockout animals to animals with a limb specific Hic1 knockout driven by the proposed limb mesenchyme specific Prrx1-Cre line.
Project description:10X Genomics Chromium 3' single-cell RNA-Seq (version 2 kit) that was sequenced in PE151 format. They are from monocellular suspensions of 8,000 dispersed embryonic limb buds. For data usage terms and conditions, please refer to http://www.genome.gov/27528022 and http://www.genome.gov/Pages/Research/ENCODE/ENCODE_Data_Use_Policy_for_External_Users_03-07-14.pdf
Project description:Numerous studies have established a critical role for BMP signaling in skeletal development. In the developing axial skeleton, sequential SHH and BMP signals are required for specification of a chondrogenic fate in somitic tissue. A similar paradigm is thought to operate in the limb, but the signals involved are unclear. To investigate the nature of these signals we examined BMP action in mesenchymal populations derived from the early murine limb bud (~ E10.5). These populations exhibited a graded response to BMPs, in which early limb mesenchymal (EL) cells (from the distal hind limb) displayed an anti-chondrogenic response, whereas BMPs promoted chondrogenesis in older cell populations. To better understand the molecular basis of disparate BMP action in these various populations, gene expression profiling with Affymetrix microarrays was employed to identify BMP-regulated genes. These analyses showed that BMPs induced a distinct gene expression pattern in the EL cultures versus later mesenchymal limb populations (IM and LT).
Project description:The bat offers an alternative paradigm to the standard mouse and chick model of limb development as it has extremely divergent forelimbs (long digits supporting a wing) and hindlimbs (short digits and claws) due the distinct requirements of both aerial and terrestrial locomotion. We used a cross-species microarray approach to identify differentially expressed (DE) genes between the bat (Minniopterus natalensis) forelimb and hindlimb autopods at Carollia developmental stages (CS) 16 and CS17, and between the bat (CS17) and mouse (E13.5) forelimb autopods. Several DE genes were identified, including two homeobox genes, Meis2, a proximal limb-patterning gene, and Hoxd11, a gene involved in digit elongation. Both genes are significantly over-expressed in the developing bat forelimb as compared to the hindlimb and equivalently staged mouse forelimbs.