Project description:Gene expression was measured using microarrays in 8 hour postfertilization embryos, comparing control versus ethanol-treated (2 to 8 hours postfertilization) embryos. This experiment was performed to determine the gene expression changes that occur in response to ethanol treatment as a model of fetal alcohol spectrum disorder. Fetal alcohol spectrum disorder (FASD) occurs when pregnant mothers consume alcohol, causing embryonic ethanol exposure and characteristic birth defects that include craniofacial, neural and cardiac defects. Gastrulation is a particularly sensitive developmental stage for teratogen exposure, and zebrafish is an outstanding model to study gastrulation and FASD. Epiboly (spreading blastomere cells over the yolk cell), prechordal plate migration and convergence/extension cell movements are sensitive to early ethanol exposure. Here, experiments are presented to characterize mechanisms of ethanol toxicity on epiboly and gastrulation. Epiboly mechanisms include blastomere radial intercalation cell movements and yolk cell microtubule cytoskeleton pulling the embryo to the vegetal pole. Both of these processes were disrupted by ethanol exposure. Ethanol effects on cell migration also indicated that cell adhesion was affected, which was confirmed by cell aggregation assays. E-cadherin cell adhesion molecule expression and distribution, which control epiboly and gastrulation, were not affected. Gene expression microarray analysis was used to identify potential causative factors for early development defects, and expression of the cell adhesion molecule protocadherin-18a (pcdh18a), which controls epiboly, was significantly reduced in ethanol-exposed embryos. Injecting pcdh18a synthetic mRNA in ethanol-treated embryos partially rescued epiboly cell movements, including enveloping layer cell shape changes. Together, data show that epiboly and gastrulation defects induced by ethanol are multifactorial, and include yolk cell (extraembryonic tissue) microtubule cytoskeleton disruption and blastomere adhesion defects, in part caused by reduced pcdh18a expression. Control vs. ethanol-treated zebrafish embryos that were treated from 2 to 8 hours postfertilization. Total RNA from control and ethanol-treated embryos were harvested at 8 hours postfertilization.
Project description:Gene expression was measured using microarrays in 8 hour postfertilization embryos, comparing control versus ethanol-treated (2 to 8 hours postfertilization) embryos. This experiment was performed to determine the gene expression changes that occur in response to ethanol treatment as a model of fetal alcohol spectrum disorder. Fetal alcohol spectrum disorder (FASD) occurs when pregnant mothers consume alcohol, causing embryonic ethanol exposure and characteristic birth defects that include craniofacial, neural and cardiac defects. Gastrulation is a particularly sensitive developmental stage for teratogen exposure, and zebrafish is an outstanding model to study gastrulation and FASD. Epiboly (spreading blastomere cells over the yolk cell), prechordal plate migration and convergence/extension cell movements are sensitive to early ethanol exposure. Here, experiments are presented to characterize mechanisms of ethanol toxicity on epiboly and gastrulation. Epiboly mechanisms include blastomere radial intercalation cell movements and yolk cell microtubule cytoskeleton pulling the embryo to the vegetal pole. Both of these processes were disrupted by ethanol exposure. Ethanol effects on cell migration also indicated that cell adhesion was affected, which was confirmed by cell aggregation assays. E-cadherin cell adhesion molecule expression and distribution, which control epiboly and gastrulation, were not affected. Gene expression microarray analysis was used to identify potential causative factors for early development defects, and expression of the cell adhesion molecule protocadherin-18a (pcdh18a), which controls epiboly, was significantly reduced in ethanol-exposed embryos. Injecting pcdh18a synthetic mRNA in ethanol-treated embryos partially rescued epiboly cell movements, including enveloping layer cell shape changes. Together, data show that epiboly and gastrulation defects induced by ethanol are multifactorial, and include yolk cell (extraembryonic tissue) microtubule cytoskeleton disruption and blastomere adhesion defects, in part caused by reduced pcdh18a expression.
Project description:The glucose-sensing Mondo pathway regulates expression of metabolic genes in mammals. Here, we have revealed an unexpected role of this pathway in vertebrate embryonic development. We characterized Mondo pathway function in the zebrafish and showed that knock-down of mondoa impaired the early morphogenetic movement of epiboly in zebrafish embryos. Expression of nsdhl , an enzyme of cholesterol and pregnenolone synthesis, was strongly reduced in these embryos. Loss of Nsdhl function likewise impaired epiboly and led to microtubule cytoskeleton defects in the embryo, similar to MondoA loss of function. Both epiboly and microtubule cytoskeleton defects were partially restored by pregnenolone treatment. Gene disruption of mondoa perturbed epiboly with only partial penetrance, likely due to compensatory changes in the expression of cholesterol/steroid metabolism genes. Collectively, our results show a novel role for MondoA in the regulation of early vertebrate development, connecting glucose, cholesterol and steroid hormone metabolism with early embryonic cell movements.
Project description:The glucose-sensing Mondo pathway regulates expression of metabolic genes in mammals. Here, we have revealed an unexpected role of this pathway in vertebrate embryonic development. We characterized Mondo pathway function in the zebrafish and showed that knock-down of mondoa impaired the early morphogenetic movement of epiboly in zebrafish embryos. Expression of nsdhl , an enzyme of cholesterol and pregnenolone synthesis, was strongly reduced in these embryos. Loss of Nsdhl function likewise impaired epiboly and led to microtubule cytoskeleton defects in the embryo, similar to MondoA loss of function. Both epiboly and microtubule cytoskeleton defects were partially restored by pregnenolone treatment. Gene disruption of mondoa perturbed epiboly with only partial penetrance, likely due to compensatory changes in the expression of cholesterol/steroid metabolism genes. Collectively, our results show a novel role for MondoA in the regulation of early vertebrate development, connecting glucose, cholesterol and steroid hormone metabolism with early embryonic cell movements.
Project description:Transcriptional profiling of Mtx2 morphants at 30% epiboly stage, shield stage and tailbud stage of embryonic development: Coordinated cell movements of gastrulation reshape the uniform blastula into a structured gastrula with three fundamental axes and an internal germ layer of mesoderm. Genetic regulation of the forces which drive gastrulation is incompletely understood. We employed a microarray screen in zebrafish for genes which participate in epibloy, and identified many with biochemical roles in endocytosis, microtubule remodeling, cell adhesion and transcription.
Project description:Ethanol exposure during prenatal development causes fetal alcohol spectrum disorder (FASD), the most frequent preventable birth defect and neurodevelopmental disability syndrome. The molecular targets of ethanol toxicity during development are poorly understood. Developmental stages surrounding gastrulation are very sensitive to ethanol exposure. To understand the effects of ethanol on early transcripts during embryogenesis, we treated zebrafish embryos with ethanol during pre-gastrulation period and examined the transcripts by Affymetrix GeneChip microarray before gastrulation. We identified 521 significantly dysregulated genes, including 61 transcription factors in ethanol-exposed embryos. Sox2, the key regulator of pluripotency and early development was significantly reduced. Functional annotation analysis showed enrichment in transcription regulation, embryonic axes patterning, and signaling pathways, including Wnt, Notch and retinoic acid. We identified all potential genomic targets of 25 dysregulated transcription factors and compared their interactions with the ethanol-dysregulated genes. This analysis predicted that Sox2 targeted a large number of ethanol-dysregulated genes. A gene regulatory network analysis showed that many of the dysregulated genes are targeted by multiple transcription factors. Injection of sox2 mRNA partially rescued ethanol-induced gene expression, epiboly and gastrulation defects. Additional studies of this ethanol dysregulated network may identify therapeutic targets that coordinately regulate early development.
Project description:Centrosome amplification has long been recognized as a feature of human tumors, however its role in tumorigenesis remains unclear. Centrosome amplification is poorly tolerated by non-transformed cells, and, in the absence of selection, extra centrosomes are spontaneously lost. Thus, the high frequency of centrosome amplification, particularly in more aggressive tumors, raises the possibility that extra centrosomes could, in some contexts, confer advantageous characteristics that promote tumor progression. Using a three-dimensional model system and other approaches to culture human mammary epithelial cells, we find that centrosome amplification triggers cell invasion. This invasive behavior is similar to that induced by overexpression of the breast cancer oncogene ErbB2 and indeed enhances invasiveness triggered by ErbB2. We show that, through increased centrosomal microtubule nucleation, centrosome amplification increases Rac1 activity, which disrupts normal cell-cell adhesion and promotes invasion. These findings demonstrate that centrosome amplification, a structural alteration of the cytoskeleton, can promote features of malignant transformation. genome-wide human SNP 6.0 arrays from Affymetrix was used to determine the copy number changes of MCF10A cells with extra centrosomes or depleted of MCAK after grown 4 days in 3-D cultures
Project description:Background: Stathmin (STMN1) protein functions to regulate assembly of the microtubule cytoskeleton by destabilizing microtubule polymers. Stathmin over-expression has been correlated with cancer stage progression, while stathmin depletion leads to death of some cancer cell lines in culture. In contrast, stathmin-null mice are viable with minor axonopathies and loss of innate fear response. Several stathmin binding partners, in addition to tubulin, have been shown to affect cell motility in culture. To expand our understanding of stathmin function in normal cells, we compared gene expression profiles, measured by microarray and qRT-PCR, of mouse embryo fibroblasts isolated from STMN1+/+ and STMN1-/- mice to determine the transcriptome level changes present in the genetic knock-out of stathmin. Results: Microarray analysis of STMN1 loss at a fold change threshold of 2.0 revealed expression changes for 437 genes, of which 269 were up-regulated and 168 were down-regulated. Microarray data and qRT-PCR analysis of mRNA expression demonstrated changes in the message levels for STMN4, encoding RB3, a protein related to stathmin, and in alterations to many tubulin isotype mRNAs. KEGG Pathway analysis of the microarray data indicated changes to cell motility-related genes, and qRT-PCR plates specific for focal adhesion and ECM proteins generally confirmed the microarray data. Several microtubule assembly regulators and motors were also differentially regulated in STMN1-/- cells, but these changes should not compensate for loss of stathmin. Conclusions: Approximately 50% of genes up or down regulated (at a fold change of ≥ 2) in STMN1-/- mouse embryo fibroblasts function broadly in cell adhesion and motility. These results support models indicating a role for stathmin in regulating cell locomotion, but also suggest that this functional activity may involve changes to the cohort of proteins expressed in the cell, rather than as a direct consequence of stathmin-dependent regulation of the microtubule cytoskeleton. Gene expression of mouse embryo fibroblasts lacking stathmin reveal changes in genes contributing to cell motility Two-color Agilent 4x44k chips with dye-swap on 2 of 4 arrays. Replicate data presented.
Project description:Centrosome amplification has long been recognized as a feature of human tumors, however its role in tumorigenesis remains unclear. Centrosome amplification is poorly tolerated by non-transformed cells, and, in the absence of selection, extra centrosomes are spontaneously lost. Thus, the high frequency of centrosome amplification, particularly in more aggressive tumors, raises the possibility that extra centrosomes could, in some contexts, confer advantageous characteristics that promote tumor progression. Using a three-dimensional model system and other approaches to culture human mammary epithelial cells, we find that centrosome amplification triggers cell invasion. This invasive behavior is similar to that induced by overexpression of the breast cancer oncogene ErbB2 and indeed enhances invasiveness triggered by ErbB2. We show that, through increased centrosomal microtubule nucleation, centrosome amplification increases Rac1 activity, which disrupts normal cell-cell adhesion and promotes invasion. These findings demonstrate that centrosome amplification, a structural alteration of the cytoskeleton, can promote features of malignant transformation.
Project description:drl expression initiates during gastrulation and condenses as a band of cells at the prospective lateral embryo margin. In late epiboly, drl:EGFP is detectable as a band of scattered EGFP-fluorescent cells; after gastrulation, drl:EGFP-positive cells coalesce at the embryo margin that then in somitogenesis break down into the anterior and posterior lateral plate with subsequent cell migrations that form the posterior vascular/hematopoietic stripes and the anterior cardiovascular and myeloid precursors. Data is as published in Mosimann & Panakova et al (Nature Communications, 2015)