The Methyl-CpG Binding Proteins Mecp2, Mbd2 and Kaiso Are Dispensable for Mouse Embryogenesis, but Play a Redundant Function in Neural Differentiation

Background The precise molecular changes that occur when a neural stem (NS) cell switches from a programme of self-renewal to commit towards a specific lineage are not currently well understood. However it is clear that control of gene expression plays an important role in this process. DNA methylation, a mark of transcriptionally silent chromatin, has similarly been shown to play important roles in neural cell fate commitment in vivo. While DNA methylation is known to play important roles in neural specification during embryonic development, no such role has been shown for any of the methyl-CpG binding proteins (Mecps) in mice. Methodology/Principal Findings To explore the role of DNA methylation in neural cell fate decisions, we have investigated the function of Mecps in mouse development and in neural stem cell derivation, maintenance, and differentiation. In order to test whether the absence of phenotype in singly-mutant animals could be due to functional redundancy between Mecps, we created mice and neural stem cells simultaneously lacking Mecp2, Mbd2 and Zbtb33. No evidence for functional redundancy between these genes in embryonic development or in the derivation or maintenance of neural stem cells in culture was detectable. However evidence for a defect in neuronal commitment of triple knockout NS cells was found. Conclusions/Significance Although DNA methylation is indispensable for mammalian embryonic development, we show that simultaneous deficiency of three methyl-CpG binding proteins genes is compatible with apparently normal mouse embryogenesis. Nevertheless, we provide genetic evidence for redundancy of function between methyl-CpG binding proteins in postnatal mice.

[1]  D. Kaplan,et al.  Trk signaling regulates neural precursor cell proliferation and differentiation during cortical development , 2007, Development.

[2]  A. Bird,et al.  Mbd2 Contributes to DNA Methylation-Directed Repression of the Xist Gene , 2007, Molecular and Cellular Biology.

[3]  M. Frotscher,et al.  Defining the actual sensitivity and specificity of the neurosphere assay in stem cell biology , 2006, Nature Methods.

[4]  A. Bird,et al.  Gene Expression Analysis Exposes Mitochondrial Abnormalities in a Mouse Model of Rett Syndrome , 2006, Molecular and Cellular Biology.

[5]  J. LaSalle,et al.  Inhibitors of differentiation (ID1, ID2, ID3 and ID4) genes are neuronal targets of MeCP2 that are elevated in Rett syndrome. , 2006, Human molecular genetics.

[6]  M. D'Esposito,et al.  The X-linked methyl binding protein gene Kaiso is highly expressed in brain but is not mutated in Rett syndrome patients. , 2006, Gene.

[7]  A. Bird,et al.  Genomic DNA methylation: the mark and its mediators. , 2006, Trends in biochemical sciences.

[8]  A. Bird,et al.  Kaiso-Deficient Mice Show Resistance to Intestinal Cancer , 2006, Molecular and Cellular Biology.

[9]  Guillaume J. Filion,et al.  A Family of Human Zinc Finger Proteins That Bind Methylated DNA and Repress Transcription , 2006, Molecular and Cellular Biology.

[10]  M. Wegner,et al.  From stem cells to neurons and glia: a Soxist's view of neural development , 2005, Trends in Neurosciences.

[11]  A. Bird,et al.  DNA binding selectivity of MeCP2 due to a requirement for A/T sequences adjacent to methyl-CpG. , 2005, Molecular cell.

[12]  Austin G Smith,et al.  Niche-Independent Symmetrical Self-Renewal of a Mammalian Tissue Stem Cell , 2005, PLoS biology.

[13]  Guoping Fan,et al.  DNA methylation controls the timing of astrogliogenesis through regulation of JAK-STAT signaling , 2005, Development.

[14]  A. Bird,et al.  Up-regulation of glucocorticoid-regulated genes in a mouse model of Rett syndrome. , 2005, Human molecular genetics.

[15]  V. Episkopou.  SOX2 functions in adult neural stem cells , 2005, Trends in Neurosciences.

[16]  R. Meehan,et al.  Kaiso is a genome-wide repressor of transcription that is essential for amphibian development , 2004, Development.

[17]  J. Daniel,et al.  Non-canonical Wnt signals are modulated by the Kaiso transcriptional repressor and p120-catenin , 2004, Nature Cell Biology.

[18]  Noriyuki Kishi,et al.  MECP2 is progressively expressed in post-migratory neurons and is involved in neuronal maturation rather than cell fate decisions , 2004, Molecular and Cellular Neuroscience.

[19]  G. Ronnett,et al.  The transcriptional repressor Mecp2 regulates terminal neuronal differentiation , 2004, Molecular and Cellular Neuroscience.

[20]  S. Tajima,et al.  Xenopus MBD3 plays a crucial role in an early stage of development. , 2004, Developmental biology.

[21]  A. Bird,et al.  Mbd1 Is Recruited to both Methylated and Nonmethylated CpGs via Distinct DNA Binding Domains , 2004, Molecular and Cellular Biology.

[22]  Daisuke Hattori,et al.  DNA Methylation-Related Chromatin Remodeling in Activity-Dependent Bdnf Gene Regulation , 2003, Science.

[23]  Eric C. Griffith,et al.  Derepression of BDNF Transcription Involves Calcium-Dependent Phosphorylation of MeCP2 , 2003, Science.

[24]  Jun Qin,et al.  N-CoR mediates DNA methylation-dependent repression through a methyl CpG binding protein Kaiso. , 2003, Molecular cell.

[25]  H. Zoghbi,et al.  A mutant form of MeCP2 protein associated with human Rett syndrome cannot be displaced from methylated DNA by notch in Xenopus embryos. , 2003, Molecular cell.

[26]  A. Bird,et al.  Deficiency of Mbd2 suppresses intestinal tumorigenesis , 2003, Nature Genetics.

[27]  E. Lein,et al.  Mice lacking methyl-CpG binding protein 1 have deficits in adult neurogenesis and hippocampal function , 2003, Proceedings of the National Academy of Sciences of the United States of America.

[28]  S. Tweedie,et al.  The methyl-CpG binding domain and the evolving role of DNA methylation in animals. , 2003, Trends in genetics : TIG.

[29]  Austin G Smith,et al.  Conversion of embryonic stem cells into neuroectodermal precursors in adherent monoculture , 2003, Nature Biotechnology.

[30]  F. Ishikawa,et al.  The mCpG-binding Domain of Human MBD3 Does Not Bind to mCpG but Interacts with NuRD/Mi2 Components HDAC1 and MTA2* , 2002, The Journal of Biological Chemistry.

[31]  Albert B. Reynolds,et al.  The p120ctn-binding partner Kaiso is a bi-modal DNA-binding protein that recognizes both a sequence-specific consensus and methylated CpG dinucleotides , 2002, Nucleic Acids Res..

[32]  A. Bird,et al.  Gene silencing quantitatively controls the function of a developmental trans-activator. , 2002, Molecular cell.

[33]  M. Nakao,et al.  DNA methylation is a critical cell-intrinsic determinant of astrocyte differentiation in the fetal brain. , 2001, Developmental cell.

[34]  W. Bickmore,et al.  Human diseases with underlying defects in chromatin structure and modification. , 2001, Human molecular genetics.

[35]  A. Bird,et al.  The p120 catenin partner Kaiso is a DNA methylation-dependent transcriptional repressor. , 2001, Genes & development.

[36]  A. Bird,et al.  Closely related proteins MBD2 and MBD3 play distinctive but interacting roles in mouse development. , 2001, Genes & development.

[37]  R. Jaenisch,et al.  Deficiency of methyl-CpG binding protein-2 in CNS neurons results in a Rett-like phenotype in mice , 2001, Nature Genetics.

[38]  R. Jaenisch,et al.  DNA Hypomethylation Perturbs the Function and Survival of CNS Neurons in Postnatal Animals , 2001, The Journal of Neuroscience.

[39]  Irving L. Weissman,et al.  A Genetic Analysis of Neural Progenitor Differentiation , 2001, Neuron.

[40]  D. Haber,et al.  DNA Methyltransferases Dnmt3a and Dnmt3b Are Essential for De Novo Methylation and Mammalian Development , 1999, Cell.

[41]  H. Zoghbi,et al.  Rett syndrome is caused by mutations in X-linked MECP2, encoding methyl-CpG-binding protein 2 , 1999, Nature Genetics.

[42]  A. Bird,et al.  The thymine glycosylase MBD4 can bind to the product of deamination at methylated CpG sites , 1999, Nature.

[43]  M W Simmen,et al.  Nonmethylated transposable elements and methylated genes in a chordate genome. , 1999, Science.

[44]  C. Walsh,et al.  Transcription of IAP endogenous retroviruses is constrained by cytosine methylation , 1998, Nature Genetics.

[45]  A. Bird,et al.  Identification and Characterization of a Family of Mammalian Methyl-CpG Binding Proteins , 1998, Molecular and Cellular Biology.

[46]  S. Cross,et al.  A component of the transcriptional represser MeCP1 shares a motif with DNA methyltransferase and HRX proteins , 1997, Nature Genetics.

[47]  S Tweedie,et al.  Methylation of genomes and genes at the invertebrate-vertebrate boundary , 1997, Molecular and cellular biology.

[48]  C. Tabin,et al.  Hox mutations au naturel , 1996, Nature Genetics.

[49]  R. Jaenisch,et al.  Loss of methylation activates Xist in somatic but not in embryonic cells. , 1995, Genes & development.

[50]  A. Bird,et al.  Gene number, noise reduction and biological complexity. , 1995, Trends in genetics : TIG.

[51]  Rudolf Jaenisch,et al.  Role for DNA methylation in genomic imprinting , 1993, Nature.

[52]  A. Bird,et al.  Dissection of the methyl-CpG binding domain from the chromosomal protein MeCP2. , 1993, Nucleic acids research.

[53]  Rudolf Jaenisch,et al.  Targeted mutation of the DNA methyltransferase gene results in embryonic lethality , 1992, Cell.

[54]  T. Bestor,et al.  DNA methylation: evolution of a bacterial immune function into a regulator of gene expression and genome structure in higher eukaryotes. , 1990, Philosophical transactions of the Royal Society of London. Series B, Biological sciences.

[55]  Jan-Fang Cheng,et al.  Loss of silent-chromatin looping and impaired imprinting of DLX5 in Rett syndrome , 2005, Nature Genetics.

[56]  A. Bird,et al.  A mouse Mecp2-null mutation causes neurological symptoms that mimic Rett syndrome , 2001, Nature Genetics.

[57]  Matthew Tudor,et al.  Loss of genomic methylation causes p53-dependent apoptosis and epigenetic deregulation , 2001, Nature Genetics.