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: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:We set out to characterize the gene expression changes which take place during chondrogenesis in the developing mouse limb. RNA derived from pre-condensed mesenchyme, mesenchymal condensations, and cartilage anlagen representing the earliest stages of tibial and fibular development was analysed by whole genome microarray analysis, and revealed 931 genes differentially expressed in these tissues. Among them were 892 genes not previously identified during the initation of chondrogenesis, including members of the Bmp, Wnt, Gdf, Sox, and Fox gene families. These microarray data were validated by qPCR, in situ hybridisation, and analysis of numerous genes already implicated in chondrogenesis in the scientific literature.
Project description:We set out to characterize the gene expression changes which take place during chondrogenesis in the developing mouse limb. RNA derived from pre-condensed mesenchyme, mesenchymal condensations, and cartilage anlagen representing the earliest stages of tibial and fibular development was analysed by whole genome microarray analysis, and revealed 931 genes differentially expressed in these tissues. Among them were 892 genes not previously identified during the initation of chondrogenesis, including members of the Bmp, Wnt, Gdf, Sox, and Fox gene families. These microarray data were validated by qPCR, in situ hybridisation, and analysis of numerous genes already implicated in chondrogenesis in the scientific literature. 231 sections from a total of four 11.5dpc mouse hind limbs, three 12.5dpc mouse hind limbs, and four 13.5dpc mouse hind limbs (all from separate mice) were microdissected, and tissues from each time point were pooled. Thus, this experiment consisted of one replicate only.
Project description:Heart valve formation initiates when endothelial cells of the heart transform into mesenchyme and populate the cardiac cushions. The transcription factor, SOX9, is highly expressed in the cardiac cushion mesenchyme, and is essential for heart valve development. Loss of Sox9 in mouse cardiac cushion mesenchyme alters cell proliferation, embryonic survival, and disrupts valve formation. Despite this important role, little is known regarding how SOX9 regulates heart valve formation or its transcriptional targets. Therefore, we mapped putative SOX9 binding sites by ChIP-Seq in embryonic day (E) 12.5 heart valves, a stage at which the valve mesenchyme is actively proliferating and initiating differentiation. Embryonic heart valves have been shown to express a high number of genes that are associated with chondrogenesis, including several extracellular matrix proteins and transcription factors that regulate chondrogenesis. Consequently, we compared regions of putative SOX9 DNA-binding between E12.5 heart valves and E12.5 limb buds. We identified context-dependent and contextâindependent SOX9 interacting regions throughout the genome. Analysis of context-independent SOX9 binding suggests an extensive role for SOX9 across tissues in regulating proliferation-associated genes including key components of the AP-1 complex. Integrative analysis of tissue-specific SOX9 interacting regions and gene expression profiles on Sox9-deficient heart valves demonstrated that SOX9 controls the expression of several transcription factors with previously identified roles in heart valve development, including Twist1, Sox4, Mecom/Evi1 and Pitx2. Together, our data identifies SOX9 coordinated transcriptional hierarchies that control cell proliferation and differentiation during valve formation. Examination of SOX9 binding sites in E12.5 atrioventricular canal (AVC) and E12.5 embryonic limb and mRNA expression profiling in E12.5 WT and Sox9 mutant AVCs, in duplicate.
Project description:The importance of unanchored Ub in innate immunity has been shown only for a limited number of unanchored Ub-interactors. We investigated what additional cellular factors interact with unanchored Ub and whether unanchored Ub plays a broader role in innate immunity. To identify unanchored Ub-interacting factors from murine lungs, we used His-tagged recombinant poly-Ub chains as bait. These chains were mixed with lung tissue lysates and protein complexes were isolated with Ni-NTA beads. Sample elutions were subjected to mass spectrometry (LC-MSMS) analysis.