Project description:The Lim1 gene has essential functions during several stages of kidney development. In particular, a tissue specific knockout in the early metanephric mesenchyme results in the formation of the earliest nephron precursor, the renal vesicle, but failure of this structure to progress to the next stage, the comma shaped body. To better understand the molecular nature of this developmental arrest we used a laser capture microdissection-microarray strategy to examine the perturbed gene expression pattern of the mutant renal vesicles. Among the genes found differently expressed were Chrdl2, an inhibitor of BMP signaling, the pro-apoptotic factor Bmf, as well as myob5, an atypical myosin which modulates chemokine and transferring signaling, and pdgfr1, which is important in epithelial folding. Of particular interest, the microarray data indicated that the Dkk1 gene, which encodes an inhibitor of Wnt signaling, was downregulated nine fold in mutants. This was confirmed by in situ hybridizations. It is interesting to note that Lim1 and Dkk1 mutant mice have striking similarities in phenotype. These results suggest that the Dkk1 gene might be a key downstream effector of Lim1 function. Keywords: Lim1 mutant, kidney development, gene expression profile comparison
Project description:The Lim1 gene has essential functions during several stages of kidney development. In particular, a tissue specific knockout in the early metanephric mesenchyme results in the formation of the earliest nephron precursor, the renal vesicle, but failure of this structure to progress to the next stage, the comma shaped body. To better understand the molecular nature of this developmental arrest we used a laser capture microdissection-microarray strategy to examine the perturbed gene expression pattern of the mutant renal vesicles. Among the genes found differently expressed were Chrdl2, an inhibitor of BMP signaling, the pro-apoptotic factor Bmf, as well as myob5, an atypical myosin which modulates chemokine and transferring signaling, and pdgfr1, which is important in epithelial folding. Of particular interest, the microarray data indicated that the Dkk1 gene, which encodes an inhibitor of Wnt signaling, was downregulated nine fold in mutants. This was confirmed by in situ hybridizations. It is interesting to note that Lim1 and Dkk1 mutant mice have striking similarities in phenotype. These results suggest that the Dkk1 gene might be a key downstream effector of Lim1 function. Experiment Overall Design: We compared gene expression profiles of wild type and mutant Lim1 renal vesicles, which were isolated from E12.5 kidneys by laser capture microdissection. Nine biological independent samples were examined, with four mutant and five wild type. Each sample included approximately 30-50 renal vesicles. Detailed protocols are described at GUDMAP.org
Project description:BACKGROUND: Lim1 is a homeobox gene that is essential for nephrogenesis. During metanephric kidney development, Lim1 is expressed in the nephric duct, ureteric buds, and the induced metanephric mesenchyme. Conditional ablation of Lim1 in the metanephric mesenchyme blocks the formation of nephrons at the nephric vesicle stage, leading to the production of small, non-functional kidneys that lack nephrons. METHODS: In the present study, we used Affymetrix probe arrays to screen for nephron-specific genes by comparing the expression profiles of control and Lim1 conditional mutant kidneys. Kidneys from two developmental stages, embryonic day 14.5 (E14.5) and 18.5 (E18.5), were examined. RESULTS: Comparison of E18.5 kidney expression profiles generated a list of 465 nephron-specific gene candidates that showed a more than 2-fold increase in their expression level in control kidney versus the Lim1 conditional mutant kidney. Computational analysis confirmed that this screen enriched for kidney-specific genes. Furthermore, at least twenty-eight of the top fifty (56%) candidates (or their vertebrate orthologs) were previously reported to have a nephron-specific expression pattern. Our analysis of E14.5 expression data yielded 41 candidate genes that are up-regulated in the control kidneys compared to the conditional mutants. Three of them are related to the Notch signaling pathway that is known to be important in cell fate determination and nephron patterning. CONCLUSIONS: Therefore, we demonstrate that Lim1 conditional mutant kidneys serve as a novel tissue source for comprehensive expression studies and provide a means to identify nephron-specific genes. Keywords: tissue specificity, time course, development, kidney, metanephric mesenchyme, nephron, Lim1, knockout mice, conditional knockout
Project description:E11.5 metanephric mesenchyme and ureteric bud were dissected from the E11.5 kidney rudiment using fine manual microdissection (ureteric bud only) or both fine manual microdissection and laser capture microdissection (metanephric mesenchyme) to define the gene expression profiles of these structures. Additionally, HoxA11, HoxD11 compound null E11.5 metanephric mesenchyme was obtained through laser capture microdissection allowing analysis of possible Hox targets in kidney development. Targets from multiple biological replicates of each were generated and the expression profiles were determined using Affymetrix MOE430_v2 arrays. Keywords: embryonic metanephric kidney, kidney development, Hoxa11, Hoxd11, compound null targeted mice
Project description:The long term objective is to create an encyclopedia of the expression levels of all genes in multiple components of the developing kidney. The central thesis is straightforward. The combination of laser capture microdissection (LCM) plus microarray analysis offers a powerful, efficient and effective method for the creation of a global gene expression atlas of the developing kidney. Microarrays with essentially complete genome coverage can be used to quantitate expression levels of every gene in laser capture microdissected components of the developing kidney. The ensuing rapid read-out provides an expression atlas that is more sensitive, more economical and more complete than would be possible by in situ hybridizations alone. Keywords: Comparison of kidney components.
Project description:The long term objective is to create an encyclopedia of the expression levels of all genes in multiple components of the developing kidney. The central thesis is straightforward. The combination of laser capture microdissection (LCM) plus microarray analysis offers a powerful, efficient and effective method for the creation of a global gene expression atlas of the developing kidney. Microarrays with essentially complete genome coverage can be used to quantitate expression levels of every gene in laser capture microdissected components of the developing kidney. The ensuing rapid read-out provides an expression atlas that is more sensitive, more economical and more complete than would be possible by in situ hybridizations alone. Keywords: Comparison of kidney components.
Project description:The long term objective is to create an encyclopedia of the expression levels of all genes in multiple components of the developing kidney. The central thesis is straightforward. The combination of laser capture microdissection (LCM) plus microarray analysis offers a powerful, efficient and effective method for the creation of a global gene expression atlas of the developing kidney. Microarrays with essentially complete genome coverage can be used to quantitate expression levels of every gene in laser capture microdissected components of the developing kidney. The ensuing rapid read-out provides an expression atlas that is more sensitive, more economical and more complete than would be possible by in situ hybridizations alone. Keywords: Comparison of kidney components.
Project description:The long term objective is to create an encyclopedia of the expression levels of all genes in multiple components of the developing kidney. The central thesis is straightforward. The combination of laser capture microdissection (LCM) plus microarray analysis offers a powerful, efficient and effective method for the creation of a global gene expression atlas of the developing kidney. Microarrays with essentially complete genome coverage can be used to quantitate expression levels of every gene in laser capture microdissected components of the developing kidney. The ensuing rapid read-out provides an expression atlas that is more sensitive, more economical and more complete than would be possible by in situ hybridizations alone. Keywords: Comparison of kidney components. At different developmental time points we isolate discrete elements of the kidney by using laser capture microdissection and then define their gene expression profiles with microarrays.
Project description:The long term objective is to create an encyclopedia of the expression levels of all genes in multiple components of the developing kidney. The central thesis is straightforward. The combination of laser capture microdissection (LCM) plus microarray analysis offers a powerful, efficient and effective method for the creation of a global gene expression atlas of the developing kidney. Microarrays with essentially complete genome coverage can be used to quantitate expression levels of every gene in laser capture microdissected components of the developing kidney. The ensuing rapid read-out provides an expression atlas that is more sensitive, more economical and more complete than would be possible by in situ hybridizations alone. Experiment Overall Design: At different developmental time points we isolate discrete elements of the kidney by using laser capture microdissection and then define their gene expression profiles with microarrays.
Project description:The long term objective is to create an encyclopedia of the expression levels of all genes in multiple components of the developing kidney. The central thesis is straightforward. The combination of laser capture microdissection (LCM) plus microarray analysis offers a powerful, efficient and effective method for the creation of a global gene expression atlas of the developing kidney. Microarrays with essentially complete genome coverage can be used to quantitate expression levels of every gene in laser capture microdissected components of the developing kidney. The ensuing rapid read-out provides an expression atlas that is more sensitive, more economical and more complete than would be possible by in situ hybridizations alone. Experiment Overall Design: At different developmental time points we isolate discrete elements of the kidney by using laser capture microdissection and then define their gene expression profiles with microarrays.