Here we report the characterization of a novel role for the retinoblastoma protein (pRb) as a regulator of osteoblast adhesion. Abrogation of pRb in osteoblasts resulted in aberrant cadherin expression and loss of adherens junctions. This produced defects suggestive of a transformed phenotype such as impaired cell-to-cell adhesion, loss of contact-dependent growth arrest, and the capacity to evade anoikis. This also resulted in profound abnormalities in bone structure. Consistent with this, microarray analyses showed that pRb regulates a wide repertoire of osteoblast cell adhesion genes. In addition, pRb loss also resulted in altered expression and function of several known regulators of cellular adhesion and adherens junction assembly, such as the Rho GTPase Rac1 and the merlin tumor suppressor. Taken together, our results show that pRb controls cell adhesion by regulating the expression and adherens junction components and by regulating the function of molecules involved in adherens junction assembly and stability.
A role for the retinoblastoma protein as a regulator of mouse osteoblast cell adhesion: implications for osteogenesis and osteosarcoma formation.
Specimen part
View SamplesThe mammalian liver, the largest solid organ in the body, accomplishes multiple critical roles necessary to preserve homeostasis. Human liver diseases are debilitating, costly and very often result in death. Uncovering developmental mechanisms that establish the complex architecture of the liver or generate the cellular diversity of this organ is necessary to develop more adequate methods to prevent, diagnose and cure liver diseases. This study investigated the role of the homeobox gene Prox1 during mouse hepatogenesis.
Prox1 ablation in hepatic progenitors causes defective hepatocyte specification and increases biliary cell commitment.
Specimen part
View SamplesAlterations in the expression of key transcription factors can be harmful for pancreatic beta cell homeostasis and could lead to diabetes. This study uncovered that Prox1 overexpression obstructs beta cell maturation and results in severe hyperglycemia.
Lack of Prox1 Downregulation Disrupts the Expansion and Maturation of Postnatal Murine β-Cells.
Specimen part
View SamplesGlis3 mutant mice (Glis3zf/zf) die within the first week after birth due to overt diabetes, evidenced by hyperglycemia and hypoinsulinemia. Histopathological analysis showed that Glis3zf/zf mice develop a pancreatic phenotype with a dramatic loss of beta- (insulin) and delta- (somatostatin) cells contrasting a smaller relative loss of alpha- (glucagon), PP- (pancreatic polypeptide), and epsilon- (ghrelin) cells. Glis3zf/zf mice develop ductal cysts with decreased number of primary cilia, while the acini are not significantly affected. Gene expression profiling by microarray analysis demonstrated that the expression of terminal hormonal genes and several transcription factors important in endocrine development were significantly deregulated in Glis3zf/zf mice. During pancreatic development, Glis3 mRNA expression is induced during the secondary transition, a stage of cell lineage specification and extensive patterning. Changes in pancreatic development of Glis3zf/zf mice are noted during and after this stage. The population of pancreatic progenitors appears not to be greatly affected in Glis3zf/zf mice; however, the number of neurogenin 3 (Ngn3) positive, endocrine progenitors is significantly reduced. Our study indicates that Glis3 plays a key role in cell lineage specification, particularly the development of mature pancreatic beta-cells. In addition, we identified evidence that Glis3 regulates insulin gene expression through two Glis-binding sites in its proximal promoter indicating that Glis3 is a regulator of insulin gene expression.
Transcription factor Glis3, a novel critical player in the regulation of pancreatic beta-cell development and insulin gene expression.
Specimen part
View SamplesOligonucleotide microarrays were used to establish a profile for gene expression in wild-type airway epithelial cells after paramyxoviral infection.
Airway epithelial versus immune cell Stat1 function for innate defense against respiratory viral infection.
Sex, Specimen part
View SamplesThe objective of this study was to obtain expression profiles of proliferative T-HEp3-GFP and dormant D-HEp3-GFP cells after one week in vivo. The second objective was find tumor cells quiescence associated genes in dormant D-HEp3 cells that are only quiescent when injected in vivo. In this case we compared cells one week growing vs. dormant for the indicated cells in chick embryo CAMs. After one week 5 embryos per cell line carrying the indicated cells were isolated, tumors collagenased as described below and sorted for GFP-high cells usig a MoFlo machine. The sorted cells > 5x10^4 were used to extract RNA and the pure RNA was used to perform expression profiling using the Affymetrix HG-u133plus2 arrays. Because of the low amount of D-HEp3 (dormant) cells recovered all tumor cells from the dormant nodules were pooled. The same was done for proliferative-sorted T-HEp3-GFP cells to allow comparisons. Arrays were performed in triplicate.
NR2F1 controls tumour cell dormancy via SOX9- and RARβ-driven quiescence programmes.
Specimen part
View SamplesThe goal of this study is to compare transcriptome profiling (RNA-seq) in controls, unaffected BMPR2 mutation carriers and affected familial pulmonary arterial hypertension patients, to elucidate a protective feature in iPS derived endothelial cells from the mutation carriers. Overall design: mRNA profiles of iPSC-ECs from unrelated control (n=3), unaffected BMPR2 mutation carriers (n=3) and FPAH patients with BMPR2 mutation (n=5).
Patient-Specific iPSC-Derived Endothelial Cells Uncover Pathways that Protect against Pulmonary Hypertension in BMPR2 Mutation Carriers.
Specimen part, Subject
View SamplesNoroviruses have been widely recognized for their importance as causative agents of non-bacterial gastroenteritis. Mouse norovirus is the only representative of the norovirus genus, family Caliciviridae, able to grow in cell culture. The aim of this study is to describe the differences in the expression profiles of MNV-1 and mock-infected macrophages (RAW 264.7 cells), in order to better understand the response of the host cell to norovirus infection.
Apoptosis in murine norovirus-infected RAW264.7 cells is associated with downregulation of survivin.
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View SamplesInsulators delimit independent transcriptional domains within genomes by constraining enhancer and silencer action. These transcriptional effects depend upon DNA recognition by insulator binding proteins that recruit partners that protect against inappropriate long range modulation of non-target promoters. Insulator binding proteins are broadly expressed during development, with largely constitutive binding to thousands of genomic sites. Yet, tissue-specific transcriptional changes result from the loss of individual insulator binding proteins. To understand the molecular basis for such effects, we are studying the classic Drosophila insulator protein Suppressor of Hairy-wing [Su(Hw)]. Genetic studies show that loss of this broadly expressed insulator protein prevents oocyte development. To determine the basis for the block in oogenesis, we coupled transcriptional analyses in su(Hw) mutant ovaries with genome-wide definition of Su(Hw) binding in this tissue. These studies identified 71 direct targets of Su(Hw) regulation, with nearly 70% of these genes showing increased RNA accumulation when Su(Hw) is lost. Surprisingly, derepressed Su(Hw) target genes correspond to genes normally highly expressed in neural tissues, suggesting that Su(Hw) has a critical role in silencing neural genes in the ovary. Support for this postulate was obtained by genetic studies. We found that oocyte production was restored in su(Hw) mutant females that carry a deletion of one allele of the elav family RNA binding protein 9 (Rbp9) gene. These su(Hw) null oocytes can be fertilized, with evidence that embryos lacking Su(Hw) show compromised development. Our studies extend the known transcriptional activities of Su(Hw), indicating that Su(Hw) can function as an insulator, activator and repressor, the latter function being essential for oogenesis. These findings highlight that insulator proteins are versatile transcriptional regulatory proteins, suggesting that tissue specific contributions to transcription result from direct regulation of individual genes.
The insulator protein Suppressor of Hairy-wing is an essential transcriptional repressor in the Drosophila ovary.
Specimen part
View SamplesSuppressor of Hairy-wing [Su(Hw)] is a multi-zinc finger DNA binding factor required for gypsy insulator function and female germline development in Drosophila. The enhancer-blocking and barrier functions of the gypsy retrotransposon involve Su(Hw) binding to twelve clustered Su(Hw) binding sites (SBSs) and recruitment of the Centrosomal Protein of 190 kD (CP190) and Modifier of mdg4 67.2 kD isoform (Mod67.2) insulator proteins. In contrast, the Su(Hw) germline function involves binding to non-clustered genomic SBSs and does not require CP190 or Mod67.2. Here, we use genome-wide expression analyses in the ovary to identify the first Su(Hw) regulated target genes.
The insulator protein Suppressor of Hairy-wing is an essential transcriptional repressor in the Drosophila ovary.
Specimen part
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