Project description:Several recent studies have suggested that genes that are longer than 100 kb are more likely to be misregulated in neurological diseases associated with synaptic dysfunction, such as autism and Rett syndrome. These length-dependent transcriptional changes are modest in Mecp2 mutant samples, but, given the low sensitivity of high-throughput transcriptome profiling technology, the statistical significance of these results needs to be re-evaluated. Here, we show that the apparent length-dependent trends previously observed in MeCP2 microarray and RNA-Sequencing datasets, particularly in genes with low-fold changes, disappeared when compared to randomized control samples. As we found no similar bias with Nanostring technology, this bias seems to be particular to PCR amplification-based platforms. Transcriptional alterations with large fold-change values, however, can reveal an authentic long gene bias. Discriminating authentic from artefactual length-dependent trends requires establishing a baseline from randomized control samples.
Project description:We compared gene expression changes in the cerebellum of mice lacking MeCP2 (Mecp2-null) and mice overexpressing MeCP2 (MECP2-transgenic). A group of postnatal neurodevelopmental disorders collectively referred to as MeCP2 disorders are caused by aberrations in the gene encoding methyl-CpG-binding protein 2 (MECP2). Loss of MeCP2 function causes Rett syndrome (RTT), whereas increased copy number of the gene causes MECP2 duplication or triplication syndromes. MeCP2 acts as a transcriptional repressor, however the gene expression changes observed in the hypothalamus of MeCP2 disorder mouse models suggest that MeCP2 can also upregulate gene expression. To determine if this dual role of MeCP2 extends beyond the hypothalamus, we studied gene expression patterns in the cerebellum of Mecp2-null and MECP2-Tg mice, modeling RTT and MECP2 duplication syndrome, respectively. We found that abnormal MeCP2 dosage causes alterations in the expression of hundreds of genes in the cerebellum. The majority of genes were upregulated in MECP2-Tg mice and downregulated in Mecp2-null mice, consistent with a role for MeCP2 as a modulator that can both increase and decrease gene expression. Interestingly, many of the genes altered in the cerebellum, particularly those increased by the presence of MeCP2 and decreased in its absence, were similarly altered in the hypothalamus. Keywords: Comparison of cerebellar gene expression data between Mecp2-null mice and Mecp2-transgenic mice Total cerebellar RNA samples were collected from Mecp2-null male mice (n=5), MECP2-transgenic male mice (n=5), and their wild type male littermates at 6 weeks of age (n=5 for each group).
Project description:We compared gene expression changes in the cerebellum of mice lacking MeCP2 (Mecp2-null) and mice overexpressing MeCP2 (MECP2-transgenic). A group of postnatal neurodevelopmental disorders collectively referred to as MeCP2 disorders are caused by aberrations in the gene encoding methyl-CpG-binding protein 2 (MECP2). Loss of MeCP2 function causes Rett syndrome (RTT), whereas increased copy number of the gene causes MECP2 duplication or triplication syndromes. MeCP2 acts as a transcriptional repressor, however the gene expression changes observed in the hypothalamus of MeCP2 disorder mouse models suggest that MeCP2 can also upregulate gene expression. To determine if this dual role of MeCP2 extends beyond the hypothalamus, we studied gene expression patterns in the cerebellum of Mecp2-null and MECP2-Tg mice, modeling RTT and MECP2 duplication syndrome, respectively. We found that abnormal MeCP2 dosage causes alterations in the expression of hundreds of genes in the cerebellum. The majority of genes were upregulated in MECP2-Tg mice and downregulated in Mecp2-null mice, consistent with a role for MeCP2 as a modulator that can both increase and decrease gene expression. Interestingly, many of the genes altered in the cerebellum, particularly those increased by the presence of MeCP2 and decreased in its absence, were similarly altered in the hypothalamus. Keywords: Comparison of cerebellar gene expression data between Mecp2-null mice and Mecp2-transgenic mice
Project description:Several recent studies have suggested that genes that are longer than 100 kb are more likely to be misregulated in neurological diseases associated with synaptic dysfunction, such as autism and Rett syndrome. These length-dependent transcriptional changes are modest in Mecp2 mutant samples, but, given the low sensitivity of high-throughput transcriptome profiling technology, the statistical significance of these results needs to be re-evaluated. Here, we show that the apparent length-dependent trends previously observed in MeCP2 microarray and RNA-Sequencing datasets, particularly in genes with low-fold changes, disappeared when compared to randomized control samples. As we found no similar bias with Nanostring technology, this bias seems to be particular to PCR amplification-based platforms. Transcriptional alterations with large fold-change values, however, can reveal an authentic long gene bias. Discriminating authentic from artefactual length-dependent trends requires establishing a baseline from randomized control samples.
Project description:We compared gene expression changes in the hypothalamus of mice lacking MeCP2 (Mecp2-null) and mice overexpressing MeCP2 (MECP2-transgenic). Mutations in the gene encoding the transcriptional repressor methyl-CpG binding protein 2 (MeCP2) cause the neurodevelopmental disorder Rett syndrome. Loss of function as well as increased dosage of MECP2 gene cause a host of neuropsychiatric disorders. To explore the molecular mechanism(s) underlying these disorders, we examined gene expression patterns in the hypothalamus of mice that either lack or overexpress MeCP2. In both models, MeCP2 dysfunction induced changes in the expression levels of thousands of genes, but surprisingly the majority of genes (~85%) appeared to be activated by MeCP2. We selected six genes and confirmed that MeCP2 binds to their promoters. Furthermore, we showed that MeCP2 associates with the transcriptional activator CREB1 at the promoter of an activated target but not a repressed target. These studies suggest that MeCP2 regulates the expression of a wide range of genes in the hypothalamus and that it can function as both an activator and repressor of transcription. Total hypothalamic RNA samples were collected from Mecp2-null male mice (n=4), MECP2-transgenic male mice (n=4), and their wild type male littermates at 6 weeks of age (n=4 for each group).
Project description:A group of postnatal neurodevelopmental disorders collectively referred to as MeCP2 disorders are caused by aberrations in the gene encoding methyl-CpG-binding protein 2 (MECP2). Loss of MeCP2 function causes Rett syndrome (RTT), whereas increased MeCP2 dosage causes MECP2 duplication or triplication syndromes. MeCP2 acts as a transcriptional repressor, however, the gene expression changes observed in the hypothalamus and cerebellum of MeCP2 disorder mouse models suggest that MeCP2 can also upregulate gene expression. In this study, we compared gene expression changes in the amygdalae of mice lacking MeCP2 (Mecp2-null) and mice overexpressing MeCP2 (MECP2-TG). We chose the amygdala because it is a neuroanatomical region implicated in the control of anxiety and social behavior, two prominent phenotypes in MECP2-TG mice, and hypothesized that transcriptional profiling of this particular brain region may reveal expression changes relevant to heightened anxiety-like behavior and abnormal social behavior. A total of 1,060 genes were altered in opposite directions in both MeCP2 mouse models compared with wild-type littermates, with ~60% up-regulated and ~40% down-regulated. Interestingly, we found a significant enrichment of anxiety- and/or social behavior-related genes among the differentially expressed genes. To determine whether these genes contribute to the anxiety and social behavior phenotypes in MECP2-TG mice, we performed genetic and pharmacologic studies and found that a reduction in Crh suppresses anxiety-like behavior, and a reduction in Oprm1 improves social approach behavior. These studies suggest that MeCP2 impacts molecular pathways involved in anxiety and social behavior, and provide insight into potential therapies for MeCP2 disorders. This study is published in Nature Genetics http://dx.doi.org/10.1038/ng.1066. Total amygdala RNA samples were collected from Mecp2-null male mice (n=4), MECP2-transgenic male mice (n=5), and their wild type male littermates at 6 weeks of age (n=4, n=5 for each group respectively).
Project description:We report the RNAseq signatures of cortex, hippocampus, striatum, liver, muscle and kidney from wild type and Mecp2 null males mice (B6.129P2(C)-Mecp2 tm1.1Bird/J, Stock No: 003890) at ~44-46 days of postnatal age
Project description:We compared gene expression changes in the hypothalamus of mice lacking MeCP2 (Mecp2-null) and mice overexpressing MeCP2 (MECP2-transgenic). Mutations in the gene encoding the transcriptional repressor methyl-CpG binding protein 2 (MeCP2) cause the neurodevelopmental disorder Rett syndrome. Loss of function as well as increased dosage of MECP2 gene cause a host of neuropsychiatric disorders. To explore the molecular mechanism(s) underlying these disorders, we examined gene expression patterns in the hypothalamus of mice that either lack or overexpress MeCP2. In both models, MeCP2 dysfunction induced changes in the expression levels of thousands of genes, but surprisingly the majority of genes (~85%) appeared to be activated by MeCP2. We selected six genes and confirmed that MeCP2 binds to their promoters. Furthermore, we showed that MeCP2 associates with the transcriptional activator CREB1 at the promoter of an activated target but not a repressed target. These studies suggest that MeCP2 regulates the expression of a wide range of genes in the hypothalamus and that it can function as both an activator and repressor of transcription.