HMGN1 contributes to the shortened latency of liver tumorigenesis by changing a chromatin structure and expression of relevant genes
Loss of the nucleosome-binding protein HMGN1 affects the rate of N-nitrosodiethylamine-induced hepatocarcinogenesis in mice.
Specimen part, Treatment
View SamplesIn most metazoan nuclei, heterochromatin is located at the nuclear periphery in contact with the nuclear lamina, which provides mechanical stability to the nucleus. We show that in cultured cells, chromatin de-compaction by the nucleosome binding protein HMGN5 decreases the sturdiness, elasticity, and rigidity of the nucleus. Mice overexpressing HMGN5, either globally or only in the heart, are normal at birth but develop hypertrophic heart with large cardiomyoctyes, deformed nuclei and disrupted lamina, and die of cardiac malfunction. Chromatin de-compaction is seen in cardiomyocytes of newborn mice but misshaped nuclei with disrupted lamina are seen only in adult cardiomyocytes, suggesting that loss of heterochromatin diminishes the ability of the nucleus to withstand the mechanical forces of the contracting heart. Thus, heterochromatin enhances the ability of the nuclear lamina to maintain the sturdiness and shape of the eukaryotic nucleus; a structural role for chromatin that is distinct from its genetic functions.
Chromatin decompaction by the nucleosomal binding protein HMGN5 impairs nuclear sturdiness.
Specimen part
View SamplesEpidermal stem cells ensure proper faring of skin homeostatic processes under both physiological and challenging conditions. Currently, the molecular events underpinning ageing within the epidermal stem cell niche are poorly understood.
In Silico Analysis of the Age-Dependent Evolution of the Transcriptome of Mouse Skin Stem Cells.
Age, Specimen part
View SamplesHMGN (high mobility group N) is a family of intrinsically disordered nuclear proteins that binds to nucleosomes, alters the structure of chromatin and affects transcription. A major unresolved question is the extent of functional specificity, or redundancy, between the various members of the HMGN protein family.
Effects of HMGN variants on the cellular transcription profile.
Specimen part
View SamplesWe have used microarray technology to identify the transcriptional targets of Rho subfamily GTPases. This analysis indicated that murine fibroblasts transformed by these proteins show similar transcriptomal profiles. Functional annotation of the regulated genes indicate that Rho subfamily GTPases target a wide spectrum of biological functions, although loci encoding proteins linked to proliferation and DNA synthesis/transcription are up-regulated preferentially. Rho proteins promote four main networks of interacting proteins nucleated around E2F, c-Jun, c-Myc, and p53. Of those, E2F, c-Jun and c-Myc are essential for the maintenance of cell transformation. Inhibition of Rock, one of the main Rho GTPase targets, leads to small changes in the transcriptome of Rho-transformed cells. Rock inhibition decreases c-myc gene expression without affecting the E2F and c-Jun pathways. Loss-of-function studies demonstrate that c-Myc is important for the blockage of cell-contact inhibition rather than for promoting the proliferation of Rho-transformed cells. However, c-Myc overexpression does not bypass the inhibition of cell transformation induced by Rock blockage, indicating that c-Myc is essential, but not sufficient, for Rock-dependent transformation. These results reveal the complexity of the genetic program orchestrated by the Rho subfamily and pinpoint protein networks that mediate different aspects of the malignant phenotype of Rho-transformed cells
Transcriptomal profiling of the cellular transformation induced by Rho subfamily GTPases.
No sample metadata fields
View SamplesThe effect of HMGN1 protein on gene expression of mouse ESC, NP and Neurons were investigated by comparing the transcriptome between Hmgn1+/+ and Hmgn1 -/- cells.
HMGN1 modulates nucleosome occupancy and DNase I hypersensitivity at the CpG island promoters of embryonic stem cells.
Specimen part
View SamplesChromatin architectural protein NSBP1/HMGN5 belongs to the family of HMGN proteins which specifically interact with nucleosomes via Nucleosome Binding Domain, unfold chromatin and affect transcription. Mouse NSBP1 is a new and uncharacterized member of HMGN protein family. NSBP1 is a nuclear protein which is localized to euchromatin, binds to linker histone H1 and unfolds chromatin.
The interaction of NSBP1/HMGN5 with nucleosomes in euchromatin counteracts linker histone-mediated chromatin compaction and modulates transcription.
No sample metadata fields
View SamplesNeurons exploit mRNA localization and local translation to spatio-temporally regulate gene expression during development. Local translation and retrograde transport of transcription factors regulate nuclear gene expression in response to signaling events at distal neuronal ends. Whether epigenetic factors could also be involved in such regulation is not known. We report that the mRNA encoding the high mobility group N5 (HMGN5) chromatin binding protein localizes to growth cones of both neuronal-like cells and of hippocampal neurons. We show that Hmgn5 3UTR drives growth cone localization and translation of a reporter gene, and that HMGN5 can be retrogradely transported into the nucleus along neurites. Loss of HMGN5 function induces transcriptional changes and impairs neurite outgrowth while HMGN5 overexpression induces neurite outgrowth and global chromatin decompaction. Interestingly, control of both neurite outgrowth and chromatin structure is dependent on proper growth cone localization of Hmgn5 mRNA. Our results provide the first evidence that mRNA localization and local translation might serve as a mechanism to couple the dynamic neuronal outgrowth process with chromatin regulation in the nucleus.
Growth Cone Localization of the mRNA Encoding the Chromatin Regulator HMGN5 Modulates Neurite Outgrowth.
No sample metadata fields
View SamplesThe guanosine triphosphatases of the Rho and Rac subfamilies regulate protumorigenic pathways and are activated by guanine nucleotide exchange factors (Rho GEFs), which could be potential targets for anticancer therapies. We report that two Rho GEFs, Vav2 and Vav3, play synergistic roles in breast cancer by sustaining tumor growth, neoangiogenesis, and many of the steps involved in lung-specific metastasis. The involvement of Vav proteins in these processes did not correlate with Rac1 and RhoA activity or cell migration, implying the presence of additional biological programs. Microarray analyses revealed that Vav2 and Vav3 controlled a vast transcriptional program in breast cancer cells through mechanisms that were shared between the two proteins, isoform-specific or synergistic. Furthermore, the abundance of Vav regulated transcripts was modulated by Rac1-dependent and Rac1-independent pathways. This transcriptome encoded therapeutically targetable proteins that played non redundant roles in primary tumorigenesis and lung-specific metastasis, such as integrin-linked kinase (Ilk), the transforming growth factorb family ligand inhibin bA, cyclooxygenase-2, and the epithelial cell adhesion molecule Tacstd2. It also contained gene signatures that predicted disease outcome in breast cancer patients. These results identify possible targets for treating breast cancer and lung metastases and provide a potential diagnostic tool for clinical use.
The rho exchange factors vav2 and vav3 control a lung metastasis-specific transcriptional program in breast cancer cells.
Cell line
View SamplesWe used microarrays to investigate gene expression changes induced by the inhibition of RRAS2 expression using shRNA techniques to stably knockdown the endogenous transcripts of this GTPase in human MDA-MB-231-Luc cells.
Contribution of the R-Ras2 GTP-binding protein to primary breast tumorigenesis and late-stage metastatic disease.
Cell line
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