The impact of MECP2 mutations in the expression patterns of Rett syndrome patients

Abstract

Rett syndrome (RTT), the second most common cause of mental retardation in females, has been associated with mutations in MeCP2, the archetypical member of the methyl-CpG binding domain (MBD) family of proteins. MeCP2 additionally possesses a transcriptional repression domain (TRD). We have compared the gene expression profiles of RTT-and normal female-derived lymphoblastoid cells by using cDNA microarrays. Clustering analysis allowed the classification of RTT patients according to the localization of the MeCP2 mutation (MBD or TRD) and those with clinically diagnosed RTT but without detectable MeCP2 mutations. Numerous genes were observed to be overexpressed in RTT patients compared with control samples, including excellent candidate genes for neurodevelopmental disease. Chromatin immunoprecipitation analysis confirmed that binding of MeCP2 to corresponding promoter CpG islands was lost in RTT-derived cells harboring a mutation in the region of the MECP2 gene encoding the MBD. Bisulfite genomic sequencing demonstrated that the majority of MeCP2 binding occurred in DNA sequences with methylation-associated silencing. Most importantly, the finding that these genes are also methylated and bound by MeCP2 in neuron-related cells suggests a role in this neurodevelopmental disease. Our results provide new data of the underlying mechanisms of RTT and unveil novel targets of MeCP2-mediated gene repression.

Integrated epigenomic analyses of neuronal MeCP2 reveal a role for long-range interaction with active genes

“…8A). Analysis of 11p15.5, in which MeCP2 binding is correlated with significant changes in H19 and IGF2 transcription (18,20,29,30), but not with changes in imprinted allelic expression (16,31), revealed sites in the H19-imprinting control region (ICR) (32) and flanking insulin (INS) and the dopaminergic neuronal gene tyrosine hydroxylase (TH) (SI Fig. 8B).…”

Transcriptional profiling of MCF7 breast cancer cells in response to 5‐Fluorouracil: Relationship with cell cycle changes and apoptosis, and identification of novel targets of p53

“…17 Commercial DO7, anti-acetyl H3 and anti-acetyl H4 antibodies (Upstate Biotechnologies, Lake Placid, NY) were used. Chromatin was crosslinked by adding 1.5% formaldehyde directly to culture flasks.…”

“…To investigate these issues, we performed ChIP analysis. 17 This assay can determine whether a particular transcriptional factor (in this case p53) is bound to a specific promoter in its natural chromatin state (in this case the promoters of the overexpressed genes from our microarray analysis) or whether changes in the histone acetylation pattern occur. First, we performed ChIP assays with anti-acetyl H3 and anti-acetyl H4 antibodies to check whether overexpression of these genes was mediated through changes in the histone acetylation status.…”

Dormant hypermethylated tumour suppressor genes: questions and answers

“…Characterization of MeCP2 in subsequent years led to the identification of the minimum portion with affinity for methylated DNA, ie its methyl-CpG binding domain (MBD) [56] and its transcriptional repression domain (TRD). MeCP2 germline mutations are responsible for the mental retardation disease Rett syndrome and the absence of a functional MeCP2 in these patients causes specific dysregulation of the gene expression [57]. Database searches led to the identification of additional proteins harbouring the MBD, namely MBD1, MBD2, MBD3, and MBD4 [58].…”