Dataset Information

Reelin promoter hypermethylation in schizophrenia.

ABSTRACT: Reelin mRNA and protein levels are reduced by approximately 50% in various cortical structures of postmortem brain from patients diagnosed with schizophrenia or bipolar illness with psychosis. In addition, the mRNA encoding the methylating enzyme, DNA methyltransferase 1, is up-regulated in the same neurons that coexpress reelin and glutamic acid decarboxylase 67. We have analyzed the extent and pattern of methylation within the CpG island of the reelin promoter in genomic DNA isolated from cortices of schizophrenia patients and nonpsychiatric subjects. Ten (The Stanley Foundation Neuropathology Consortium) and five (Harvard Brain Collection) schizophrenia patients and an equal number of nonpsychiatric subjects were selected from each brain collection. Genomic DNA was isolated, amplified (from base pair -527 to base pair +322) after bisulphite treatment, and sequenced. The results show that within the promoter region there were interesting regional variations. There was increased methylation at positions -134 and 139, which is particularly important for regulation, because this portion of the promoter is functionally competent based on transient transfection assays. This promoter region binds a protein present in neuronal precursor nuclear extracts that express very low levels of reelin mRNA; i.e., an oligonucleotide corresponding to this region and that contains methylated cytosines binds more tightly to extracts from nonexpressing cells than the nonmethylated counterpart. Collectively, the data show that this promoter region has positive and negative properties and that the function of this complex cis element relates to its methylation status.

SUBMITTER: Grayson DR

PROVIDER: S-EPMC1166626 | biostudies-literature | 2005 Jun

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Reelin promoter hypermethylation in schizophrenia.

Grayson Dennis R DR Jia Xiaomei X Chen Ying Y Sharma Rajiv P RP Mitchell Colin P CP Guidotti Alessandro A Costa Erminio E

Proceedings of the National Academy of Sciences of the United States of America 20050616 26

Reelin mRNA and protein levels are reduced by approximately 50% in various cortical structures of postmortem brain from patients diagnosed with schizophrenia or bipolar illness with psychosis. In addition, the mRNA encoding the methylating enzyme, DNA methyltransferase 1, is up-regulated in the same neurons that coexpress reelin and glutamic acid decarboxylase 67. We have analyzed the extent and pattern of methylation within the CpG island of the reelin promoter in genomic DNA isolated from cort ...[more]

PMID: 15961543

Similar Datasets

Project description:Reln mRNA and protein levels are reduced by approximately 50% in various cortical structures of post-mortem brain from patients diagnosed with schizophrenia or bipolar illness with psychosis. To study mechanisms responsible for this down-regulation, we have analyzed the promoter of the human reelin gene. We show that the reelin promoter directs expression of a reporter construct in multiple human cell types: neuroblastoma cells (SHSY5Y), neuronal precursor cells (NT2), differentiated neurons (hNT) and hepatoma cells (HepG2). Deletion constructs confirmed the presence of multiple elements regulating Reln expression, although the promoter activity is promiscuous, i.e. activity did not correlate with expression of the endogenous gene as reflected in terms of reelin mRNA levels. Co-transfection of the -514 bp human reelin promoter with either Sp1 or Tbr1 demonstrated that these transcription factors activate reporter expression by 6- and 8.5-fold, respectively. Within 400 bp of the RNA start site there are 100 potential CpG targets for DNA methylation. Retinoic acid (RA)-induced differentiation of NT2 cells to hNT neurons was accompanied by increased reelin expression and by the appearance of three DNase I hypersensitive sites 5' to the RNA start site. RA-induced differentiation was also associated with demethylation of the reelin promoter. To test if methylation silenced reelin expression, we methylated the promoter in vitro prior to transfection. In addition, we treated NT2 cells with the methylation inhibitor aza-2'-deoxycytidine and observed a 60-fold increase in reelin mRNA levels. The histone deacetylase inhibitors trichostatin A (TSA) and valproic acid also induced expression of the endogenous reelin promoter, although TSA was considerably more potent. These findings indicate that one determinant responsible for regulating reelin expression is the methylation status of the promoter. Our data also raise the interesting possibility that the down-regulation of reelin expression documented in psychiatric patients might be the consequence of inappropriate promoter hypermethylation.

Project description:BackgroundLeucine-rich repeat C4 protein (LRRC4) is a new member of the leucine-rich repeat (LRR) superfamily. It is not only a brain-specific gene but also a novel candidate for tumor suppression. LRRC4 inactivation is commonly found in glioma cell lines and primary glioma biopsies. However, little is known about the mechanism controlling LRRC4 expression. In a previous study, we did not find any genetic alteration in LRRC4 in primary glioma, which led us to explore an alternative mechanism underlying this phenomenon.MethodsIn the present paper, we cloned the LRRC4 promoter with characteristics of a CpG island by luciferase reporter assay. Then, the CpG methylation status around the LRRC4 promoter region in glioma cell lines and primary gliomas was examined by methylation-specific PCR and bisulfite DNA sequencing. In order to demonstrate a functional association between LRRC4 promoter methylation and its gene inactivation, we performed DNA demethylation analysis with two human glioma cell lines using methylation-specific PCR and RT-PCR.ResultsThe sequence spanning positions -835 to -293 relative to the translation start site was identified as the LRRC4 promoter; this sequence is a TATA- and CAAT- less, high GC content region. It was found that LRRC4 promoter activity is strongly suppressed after treatment with SssI methylase in vitro. Furthermore, LRRC4 promoter methylation was observed by methylation-specific PCR in two glioma cell lines and all 30 primary glioma specimens, but not in normal brain tissue. Bisulfite DNA sequencing showed that most of the CpG sites were located around the LRRC4 promoter methylated in glioma cells and tissues, but not in normal brain tissue. In addition, the methylase inhibitor 5-Aza-2'-deoxycytidine could induce LRRC4 mRNA expression and LRRC4 promoter partial demethylation in SF126 and SF767 glioma cells.ConclusionMethylation-mediated inactivation of LRRC4 is a frequent and glioma-specific event, and it may be a potential biomarker for diagnosis or prognosis, or serve as a therapeutic target.

Dataset Information

Reelin promoter hypermethylation in schizophrenia.

Publications

Reelin promoter hypermethylation in schizophrenia.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets