Temporal changes of gene expression from 1-wk- to 5-wk-old rat in kidney and lung, and the effect of prior growth inhibition on these genetic changes.
Coordinated postnatal down-regulation of multiple growth-promoting genes: evidence for a genetic program limiting organ growth.
Age, Specimen part
View SamplesTemporal changes of gene expression from 1-wk- to 4-wk and 8-wk-old mouse in heart, kidney and lung. Mammalian somatic growth is rapid in early postnatal life but then slows and eventually ceases in multiple tissues. We hypothesized that there exists a postnatal gene expression program that is common to multiple tissues and is responsible for this coordinate growth deceleration. Consistent with this hypothesis, microarray analysis identified >1600 genes that were regulated with age coordinately in kidney, lung, and heart of juvenile mice, including many genes that regulate proliferation. As examples, we focused on three growth-promoting genes, Igf2, Mest, and Peg3, that were markedly downregulated with age. We conclude that there exists an extensive genetic program occurring during postnatal life. Many of the involved genes are regulated coordinately in multiple organs, including many genes that regulate cell proliferation. At least some of these are themselves apparently regulated by growth, suggesting that, in the embryo, a gene expression pattern is established that allows for rapid somatic growth of multiple tissues but then, during postnatal life, this growth leads to negative-feedback changes in gene expression that in turn slow and eventually halt somatic growth, thus imposing a fundamental limit on adult body size.
An extensive genetic program occurring during postnatal growth in multiple tissues.
Sex, Age, Specimen part
View SamplesWe present ScarTrace, a single-cell sequencing strategy that allows us to simultaneously quantify information on clonal history and cell type for thousands of single cells obtained from different organs from adult zebrafish. Using this approach we show that all blood cells types in the kidney marrow arise from a small set of multipotent embryonic. In contrast, we find that cells in the eyes, brain, and caudal tail fin arise from many embryonic progenitors, which are more restricted and produce specific cell types in the adult tissue. Next we use ScarTrace to explore when embryonic cells commit to forming either left or right organs using the eyes and brain as a model system. Lastly we monitor regeneration of the caudal tail fin and identify a subpopulation of resident macrophages that have a clonal origin that is distinct from other blood cell types. Overall design: Single cell sequencing data from cells isolated from zebrafish organs (whole kidney marrow, forebrain, hindbrain, left eye, right eye, left midbrain, right midbrain, and regenerated fin). For each cell, we provide libraries with transcritpome and with clonal information, respectively.
Whole-organism clone tracing using single-cell sequencing.
Specimen part, Subject
View SamplesThe Her-2/Neu-positive mouse breast cancer cell line was serially co-cultured with minced brain, bone marrow, and lung tissue in an intravital microscopy chamber mounted on the dorsal skinfold of nude mice, alternating with growth in vitro. Gene expression analysis was performed on the cells grown in culture after sorting and further growth in vitro. Gene expression under these growth conditions differed in time and according to the co-cultivated organ tissue. This study reveals genes that are expressed by cells as they adapt differentially to various foreign tissue microenvironments, and may represent a paradigm to discover gene expression changes that occur immediately upon extravasation when cancer metastasizes.
Effects of different tissue microenvironments on gene expression in breast cancer cells.
Cell line
View SamplesTo explore the mechanisms responsible for spatial and temporal regulation of the growth plate, we microdissected postnatal rat growth plates into their constituent zones and then used microarray analysis to characterize the changes in gene expression that occur as chondrocytes undergo spatially-associated differentiation and temporally-associated senescence.
Spatial and temporal regulation of gene expression in the mammalian growth plate.
Age
View SamplesWe used laser capture microdissection to isolate different zones of the articular cartilage from proximal tibiae of 1-week old mice, and used microarray to analyze global gene expression. Bioinformatic analysis corroborated previously known signaling pathways, such as Wnt and Bmp signaling, and implicated novel pathways, such as ephrin and integrin signaling, for spatially associated articular chondrocyte differentiation and proliferation. In addition, comparison of the spatial regulation of articular and growth plate cartilage revealed unexpected similarities between the superficial zone of the articular cartilage and the hypertrophic zone of the growth plate.
Gene expression profiling reveals similarities between the spatial architectures of postnatal articular and growth plate cartilage.
Age, Specimen part
View SamplesArticular and growth plate cartilage have comparable structures consisting of three distinct layers of chondrocytes, suggesting similar differentiation programs and therefore similar gene expression profiles. To address this hypothesis and to explore transcriptional changes that occur during the onset of articular and growth plate cartilage divergence, we used microdissection of 10-day-old rat proximal tibial epiphyses, microarray analysis, and bioinformatics to compare gene expression profiles in individual layers of articular and growth plate cartilage.
Gene expression profiling reveals similarities between the spatial architectures of postnatal articular and growth plate cartilage.
Age, Specimen part
View SamplesNotch3 is a transmembrane receptor which is critically important for the structure and myogenic response of distal arteries, particularly cerebral arteries. After activation of the receptor, the intracellular domain translocates in the nucleus to activate target genes transcription.
Transcriptome analysis for Notch3 target genes identifies Grip2 as a novel regulator of myogenic response in the cerebrovasculature.
Age, Specimen part
View SamplesBody size varies enormously among mammalian species. In small mammals, body growth is typically suppressed rapidly, within weeks, whereas in large mammals, growth is suppressed slowly, over years, allowing for a greater adult size. We recently reported evidence that body growth suppression in rodents is caused in part by a juvenile genetic program that occurs in multiple tissues simultaneously and involves the downregulation of a large set of growth-promoting genes. We hypothesized that this genetic program is conserved in large mammals but that its time course is evolutionarily modulated such that it plays out more slowly, allowing for more prolonged growth. Consistent with this hypothesis, using expression microarray analysis, we identified a set of genes that are downregulated with age in both juvenile sheep kidney and lung. This overlapping gene set was enriched for genes involved in cell proliferation and growth and showed striking similarity to a set of genes downregulated with age in multiple organs of the juvenile mouse and rat, indicating that the multiorgan juvenile genetic program previously described in rodents has been conserved in the 80 million years since sheep and rodents diverged in evolution. Using microarray and real-time PCR, we found that the pace of this program was most rapid in mice, more gradual in rats, and most gradual in sheep. The findings support the hypothesis that a growth-regulating genetic program is conserved among mammalian species but that its pace is modulated to allow more prolonged growth and therefore greater adult body size in larger mammals.
Evolutionary conservation and modulation of a juvenile growth-regulating genetic program.
Specimen part
View SamplesIn order to characterize mRNA expression in the growth plate, we microdissected postnatal rat growth plates into their constituent zones and used microarray analysis to assess the abundences of individual transcripts. Expression patterns of PTHrP and Ihh-related genes were confirmed using real-time PCR. Using a gli1-lacZ mouse, Gli1 expression, presumably representing Ihh signaling, was visualized during pre- and postnatal development.
Organization of the Indian hedgehog--parathyroid hormone-related protein system in the postnatal growth plate.
Age
View Samples