56. Beirowski B, Berek L, Adalbert R, Wagner D, Grumme DS, et al. (2004) Quantitative and qualitative analysis of Wallerian degeneration using restricted axonal labelling in YFP-H mice. J Neurosci Methods 134: 23–35. 57. Bittner T, Fuhrmann M, Burgold S, Ochs SM, Hoffmann N, et al. (2010) Multiple events lead to dendritic spine loss in triple transgenic Alzheimer’s disease mice. PLoS One 5: e15477. 58. Hansen KF, Sakamoto K, Wayman GA, Impey S, Obrietan K (2010) Transgenic miR132 alters neuronal spine density and impairs novel object recognition memory. PLoS One 5: e15497. 59. Landi S, Putignano E, Boggio EA, Pizzorusso T, Ratto GM (2011) The short- time structural plasticity of dendritic spines is altered in a model of Rett syndrome. Sci Rep 1:45: 1–7. 60. Matter C, Pribadi M, Liu X, Trachtenberg JT (2009) Delta-catenin is required for the maintenance of neural structure and function in mature cortex in vivo. Neuron 64: 320–327. 61. Migliore M, Shepherd GM (2005) Opinion: an integrated approach to classifying neuronal phenotypes. Nat Rev Neurosci 6: 810–818. 62. Molna´r Z, Cheung AF (2006) Towards the classification of subpopulations of layer V pyramidal projection neurons. Neurosci Res 55: 105–115. 63. Molyneaux BJ, Arlotta P, Menezes JR, Macklis JD (2007) Neuronal subtype specification in the cerebral cortex. Nat Rev Neurosci 8: 427–437. 64. Kriaucionis S, Bird A (2004) The major form of MeCP2 has a novel N-terminus generated by alternative splicing. Nucleic Acids Res 32: 1818–1823. 65. LaSalle JM, Goldstine J, Balmer D, Greco CM (2001) Quantitative localization of heterogeneous methyl-CpG-binding protein 2 (MeCP2) expression pheno- types in normal and Rett syndrome brain by laser scanning cytometry. Hum Mol Genet 10: 1729–1740. 66. Mullaney BC, Johnston MV, Blue ME (2004) Developmental expression of methyl-CpG binding protein 2 is dynamically regulated in the rodent brain. Neuroscience 123: 939–949. 67. Samaco RC, Nagarajan RP, Braunschweig D, LaSalle JM (2004) Multiple pathways regulate MeCP2 expression in normal brain development and exhibit defects in autism-spectrum disorders. Hum Mol Genet 13: 629–639. 68. Reichwald K, Thiesen J, Wiehe T, Weitzel J, Poustka WA, et al. (2000) Comparative sequence analysis of the MECP2-locus in human and mouse reveals new transcribed regions. Mamm Genome 11: 182–190. 69. Coy JF, Sedlacek Z, Bachner D, Delius H, Poustka A (1999) A complex pattern of evolutionary conservation and alternative polyadenylation within the long 30- untranslated region of the methyl-CpG-binding protein 2 gene (MeCP2) suggests a regulatory role in gene expression. Hum Mol Genet 8: 1253–1262. 70. Balmer D, Goldstine J, Rao YM, LaSalle JM (2003) Elevated methyl-CpG- binding protein 2 expression is acquired during postnatal human brain development and is correlated with alternative polyadenylation. J Mol Med 81: 61–68. 71. Zhou Z, Hong EJ, Cohen S, Zhao WN, Ho HY, et al. (2006) Brain-specific phosphorylation of MeCP2 regulates activity-dependent Bdnf transcription, dendritic growth, and spine maturation. Neuron 52: 255–269. 72. Tao J, Hu K, Chang Q, Wu H, Sherman NE, et al. (2009) Phosphorylation of MeCP2 at Serine 80 regulates its chromatin association and neurological function. Proc Natl Acad Sci U S A 106: 4882–4887. 73. Nan X, Campoy FJ, Bird A (1997) MeCP2 is a transcriptional repressor with abundant binding sites in genomic chromatin. Cell 88: 471–481. 74. Colantuoni C, Jeon OH, Hyder K, Chenchik A, Khimani AH, et al. (2001) Gene expression profiling in postmortem Rett Syndrome brain: differential gene expression and patient classification. Neurobiol Dis 8: 847–865. Altered Dendrites in YFP-MeCP2 Mutant Mice 75. Yasui DH, Peddada S, Bieda MC, Vallero RO, Hogart A, et al. (2007) Integrated epigenomic analyses of neuronal MeCP2 reveal a role for long-range interaction with active genes. Proc Natl Acad Sci U S A 104: 19416–19421. 76. Skene PJ, Illingworth RS, Webb S, Kerr AR, James KD, et al. (2010) Neuronal MeCP2 is expressed at near histone-octamer levels and globally alters the chromatin state. Mol Cell 37: 457–468. 77. Wu H, Tao J, Chen PJ, Shahab A, Ge W, et al. (2010) Genome-wide analysis reveals methyl-CpG-binding protein 2-dependent regulation of microRNAs in a mouse model of Rett syndrome. Proc Natl Acad Sci U S A. 78. Young JI, Hong EP, Castle JC, Crespo-Barreto J, Bowman AB, et al. (2005) Regulation of RNA splicing by the methylation-dependent transcriptional repressor methyl-CpG binding protein 2. Proc Natl Acad Sci U S A 102: 17551–17558. 79. Chahrour M, Jung SY, Shaw C, Zhou X, Wong ST, et al. (2008) MeCP2, a key contributor to neurological disease, activates and represses transcription. Science 320: 1224–1229. 80. Urdinguio RG, Lopez-Serra L, Lopez-Nieva P, Alaminos M, Diaz-Uriarte R, et al. (2008) Mecp2-null mice provide new neuronal targets for Rett syndrome. PLoS One 3: e3669. 81. Ben-Shachar S, Chahrour M, Thaller C, Shaw CA, Zoghbi HY (2009) Mouse models of MeCP2 disorders share gene expression changes in the cerebellum and hypothalamus. Hum Mol Genet 18: 2431–2442. 82. Gibson JH, Slobedman B, Harikrishnan KN, Williamson SL, Minchenko D, et al. (2010) Downstream targets of methyl CpG binding protein 2 and their abnormal expression in the frontal cortex of the human Rett syndrome brain. BMC Neurosci 11: 53. 83. Nan X, Ng HH, Johnson CA, Laherty CD, Turner BM, et al. (1998) Transcriptional repression by the methyl-CpG-binding protein MeCP2 involves a histone deacetylase complex. Nature 393: 386–389. 84. Peddada S, Yasui DH, LaSalle JM (2006) Inhibitors of differentiation (ID1, ID2, ID3 and ID4) genes are neuronal targets of MeCP2 that are elevated in Rett syndrome. Hum Mol Genet 15: 2003–2014. 85. Walters MC, Fiering S, Eidemiller J, Magis W, Groudine M, et al. (1995) Enhancers increase the probability but not the level of gene expression. Proc Natl Acad Sci U S A 92: 7125–7129. 86. Graubert TA, Hug BA, Wesselschmidt R, Hsieh CL, Ryan TM, et al. (1998) Stochastic, stage-specific mechanisms account for the variegation of a human globin transgene. Nucleic Acids Res 26: 2849–2858. 87. O’Leary DD, Stanfield BB (1985) Occipital cortical neurons with transient pyramidal tract axons extend and maintain collaterals to subcortical but not intracortical targets. Brain Res 336: 326–333. 88. Stanfield BB, O’Leary DD (1985) The transient corticospinal projection from the occipital cortex during the postnatal development of the rat. J Comp Neurol 238: 236–248. 89. Thong IG, Dreher B (1987) The development of the corticotectal pathway in the albino rat: transient projections from the visual and motor cortices. Neurosci Lett 80: 275–282. 90. Cassel S, Revel MO, Kelche C, Zwiller J (2004) Expression of the methyl-CpG- binding protein MeCP2 in rat brain. An ontogenetic study. Neurobiol Dis 15: 206–211. 91. Cohen DR, Matarazzo V, Palmer AM, Tu Y, Jeon OH, et al. (2003) Expression of MeCP2 in olfactory receptor neurons is developmentally regulated and occurs before synaptogenesis. Mol Cell Neurosci 22: 417–429. PLoS ONE | www.plosone.org 11 March 2012 | Volume 7 | Issue 3 | e31896