Project description:Meis, Prep and Pbx1 TALE homeoproteins interactions with Hox proteins are essential for development and disease. Although Meis and Prep behave similarly in vitro, their in vivo activities remain largely unexplored. We show that Prep and Meis interact with largely independent sets of genomic sites and select different DNA binding sequences, with Prep associating mostly with promoters and house-keeping genes and Meis with promoter-remote regions and developmental genes. Hox target sequences associate strongly with Meis but not with Prep binding sites, while Pbx1 cooperates with both Prep and Meis. Accordingly, Meis1 shows strong genetic interaction with Pbx1 but not with Prep1. Meis1 and Prep1 nonetheless co-regulate a subset of genes, predominantly through opposing effects. Notably, the TALE homeoprotein binding profile subdivides Hox clusters into two domains differentially regulated by Meis1 and Prep1. After duplication of the ancestral gene, Meis and Prep thus specialized their interactions but maintained significant regulatory coordination. ChIP-seq of 3 TALE proteins in E11.5 C57BL/6 embryonic mice
Project description:Meis, Prep and Pbx1 TALE homeoproteins interactions with Hox proteins are essential for development and disease. Although Meis and Prep behave similarly in vitro, their in vivo activities remain largely unexplored. We show that Prep and Meis interact with largely independent sets of genomic sites and select different DNA binding sequences, with Prep associating mostly with promoters and house-keeping genes and Meis with promoter-remote regions and developmental genes. Hox target sequences associate strongly with Meis but not with Prep binding sites, while Pbx1 cooperates with both Prep and Meis. Accordingly, Meis1 shows strong genetic interaction with Pbx1 but not with Prep1. Meis1 and Prep1 nonetheless co-regulate a subset of genes, predominantly through opposing effects. Notably, the TALE homeoprotein binding profile subdivides Hox clusters into two domains differentially regulated by Meis1 and Prep1. After duplication of the ancestral gene, Meis and Prep thus specialized their interactions but maintained significant regulatory coordination. RNA-seq of 2 Meis1 and Prep1 loss of function mutants in E11.5 C57BL/6 embryonic mice
Project description:We have defined the tumor and tumor suppressor signature for Meis1 and Prep1 (pKnox1), respectively, using ChIP-seq and RNA-seq in a cell system in which tumor suppressor Prep1 and oncogene Meis1 compete for tumorigenesis [GSE54221; GSE58802]. In this paper we report that the number of Meis1 or Prep1 DNA binding sites increases linearly with the level of expression of the two transcription factors. Overexpression of Meis1 induces tumors. At the molecular level it modifies the DNA target specificity by increasing the number of low-affinity binding sites, which results in a different choice of consensus sequences with predominance of sites normally bound by the AP1 transcription factor family. Upon concomitant overexpression of Prep1 and Meis1 tumorigenesis is inhibited. Prep1 dominates over Meis1 not only because it partially decreases Meis1 protein level but also because it prevents the binding to a substantial fraction of the low affinity binding sites. Overall, overexpression of Prep1 reverses the nature of the bound and regulated genes from stimulatory to inhibitory of signal transduction and transcription, which suppresses tumorigenesis. By identifying the Meis1 tumor signature, specific relevant signaling pathways are identified. In line with these results, tumorigenic Meis1-overexpressing cells are uniquely hypersensitive to inhibitors of the MAPK/Akt pathways. Examination of Prep1 and Meis1 in five cell type
Project description:Prep1 is a tumor-suppressor, whereas Meis1 is an oncogene. We show that to perform these activities in MEFs both proteins competitively hetero-dimerize with Pbx1. Meis1 alone transforms Prep1-deficient fibroblasts while Prep1 overexpression inhibits Meis1 tumorigenicity. Pbx1 can therefore alternatively act as oncogene or tumor-suppressor. Prep1 post-translationally controls the level of Meis1 decreasing its stability by sequestering Pbx1. The different levels of Meis1 and the presence of Prep1 are followed at the transcriptional level by the induction of specific transcriptional signatures. The decrease of Meis1 prevents Meis1 interaction with Ddx3x and Ddx5, which are essential for Meis1 tumorigenesis, and modifies the growth promoting DNA binding landscape of Meis1 to the growth controlling landscape of Prep1. Hence the key feature of Prep1 tumor inhibiting activity is the control of Meis1 stability. Examination of Prep1 and Meis1 in three cell type
Project description:Prep1 is a tumor-suppressor, whereas Meis1 is an oncogene. We show that to perform these activities in MEFs both proteins competitively hetero-dimerize with Pbx1. Meis1 alone transforms Prep1-deficient fibroblasts while Prep1 overexpression inhibits Meis1 tumorigenicity. Pbx1 can therefore alternatively act as oncogene or tumor-suppressor. Prep1 post-translationally controls the level of Meis1 decreasing its stability by sequestering Pbx1. The different levels of Meis1 and the presence of Prep1 are followed at the transcriptional level by the induction of specific transcriptional signatures. The decrease of Meis1 prevents Meis1 interaction with Ddx3x and Ddx5, which are essential for Meis1 tumorigenesis, and modifies the growth promoting DNA binding landscape of Meis1 to the growth controlling landscape of Prep1. Hence the key feature of Prep1 tumor inhibiting activity is the control of Meis1 stability. Examination of Prep1 and Meis1 in two cell types
Project description:We report the transcriptome analysis of E11.5 mouse embryonic heart presenting a reduction in Nkx2-5 expression compare to wild-type littermate. Transcriptome analysis of 3 different E11.5 hypomorphic hearts against 3 controls littermate hearts.
Project description:Microphthalmos is a rare congenital anomaly characterized by reduced eye size and visual deficits of variable degrees. Sporadic and hereditary microphthalmos has been associated to heterozygous mutations in genes fundamental for eye development. Yet, many cases are idiopathic or await the identification of molecular causes. Here we show that haploinsufficiency of Meis1, a transcription factor with an evolutionary conserved expression in the embryonic trunk, brain and sensory organs, including the eye, causes microphthalmic traits and visual impairment, in adult mice. In the trunk, Meis1 acts as a cofactor for genes of the Hox complex, mostly binding to Hox-Pbx target sequence on the DNA. By combining the analysis of Meis1 loss-of-function and conditional Meis1 functional rescue with ChIPseq and RNAseq approaches, we show that during the development of the optic cup, an Hox-free region, Meis1 binds instead to Hox/Pbx-independent Meis binding site, and coordinates, in a dose-dependent manner, retinal proliferation and differentiation by regulating the expression of components of the Notch signalling pathway. Meis1 also controls the activity of genes responsible for human microphthalmia and eye patterning so that in Meis1-/- embryos, the eye size is reduced and boundaries among the different eye territories are shifted or blurred. We thus propose that Meis1 is at the core of a genetic network implicated in microphthalmia, itself representing an additional candidate for syndromic cases of these ocular malformations. Transcriptomics and Meis1 Occupancy analysis on mouse isolated optic cups and ChIP data for histone methylation marks were obtained from about 100 eyes of E10.5 CD1 embryos.
Project description:Primary murine hematopoietic cells were retrovirally transduced with Hoxa9 cDNA, expanded in vitro before undergoing secondary infection with the cDNA of Meis1, Prep1 and the Prep1-MC mutant. RNA was extracted and transcriptomes were analyzed. Background corrections and normalisations were performed using RMA in NimbleScan 2.5