DNA Methylation of HTR2A

DNA Methylation of HTR2A, DRD2 & RELN Genes Promoters and CpG rich areas in




Mostafavi Abdolmaleky, M.D.1,2,6, Sam Thiagalingam, Ph.D.3,

Cassandra L. Smith, Ph.D. 4 , Stephen V.Faraone, Ph.D.2,5,

Kunag-hung Cheng, MS. 3 ,Rahim Shafa M.D.7, Stephen Glatt

Ph.D.1,2 , William S Stone, Ph.D. 1,2, and Ming Tsuang,




of Psychiatry, Harvard Medical School at Massachusetts Mental Health Center


Institute of Psychiatric Epidemiology and Genetics, Boston, Massachusetts


of Genetics and Genomics, Boston University School of Medicine, Boston, MA      

4Laboratory of

Molecular Biotechnology Research, Center for Advanced Biotechnology, and

Departments of Biomedical Engineering, Biology and Pharmacology, Boston

University, Boston, MA.

5Department of

Psychiatry, Harvard Medical School, Massachusetts General Hospital, Boston, MA


of Psychiatry, Iran University of Medical Sciences, Tehran, Iran


CNS Research Center, Tenet Metrowest Medical Center, Natic, MA


Service, Brockton-West Roxbury Veterans Affairs Medical Center, Brockton,



of Epidemiology, Harvard School of Public Health, Boston, Massachusetts





Cytosine methylation can prevent gene expression through the actions of four

known proteins, MeCP2, MBD1, MBD2 and MBD3 which bind to methylated DNA.

Concurrently, histones are deacetylated and the

chromatin structure of the chromosome is modified and transcription is reduced.

Methylation can be affected by dietary level of

methyl-donor components, such as methionine and folic acid. Also, the growth of

granule cells in culture medium under sub-optimal conditions resulted in

apoptosis due to a reduction in DNA methylation.


methylation increases in response to transient ischemia that endangers CNS

neurons survival, while inhibition of DNA methylation prevents brain damages.


hypoxia produces more structural brain abnormalities in schizophrenic patients

and their non schizophrenic siblings, especially with low birth weight. There is

evidence indicating that DNA methylation could be abnormal in the RELN, DRD2 and

HTR2A genes in schizophrenia and mood disorder.


Comparing the pattern and amount of DNA Methylation in the promoters and CpG

rich areas of the HTR2A, DRD2 and RELN genes in post-mortem brain tissues of

schizophrenic patients and normal controls.

Materials and methods:

Five samples for each group were provided by the Harvard Brain Tissue Resources

Center. Several primers were specified and tested for detection of the DRD2,

HTR2A and RELN genes’ promoters and CpG rich areas. The technique of direct

sequencing of sodium bisulfite-treated DNA was applied for mapping of

5-methylated cytosine and the technique of Methylation specific PCR was used to

specify the site specific methylation difference among patients and controls.


Promoter areas of these genes are sparsely methylated, however CpG rich areas

located in the non-promoter (intronic) areas are heavily methylated in patients

and controls. We found some differences between samples and controls in the

promoter area especially in the reelin gene.  However, we were unable to achieve

statistical significance due to the small sample size.  We have been provided

with an additional 105 samples from the Stanley Medical Research Institute to

overcome the small sample size problems, and have included bipolar disorder in

the project as well.  

Key words:

DNA Methylation, Schizophrenia, Bipolar, HTR2A, DRD2, RELN Gene, Frontal lobe,