Epigenetic studies of genomic retroelements in major psychosis.

This work is dedicated to the exploration of the role of epigenetic (epiG) factors in major psychosis. One of the key functions of epigenetic modification of the genome of eukaryotic cells is to suppress transcriptional activity of the retroelements. Examples of retroelements are endogenous retroviral sequences (ERVs), Alu's, and LINEs, among others, which as a rule are hypermethylated. There is evidence from schizophrenia (SCH) and other human complex diseases that some of the genomic retroelements become transcribed in the affected tissues. Our goal was to screen DNA samples from post-mortem brain tissues of individuals who were affected with major psychiatric illness for retroelements that were located in the hypomethylated fraction of the genomic DNA. Over 100 Alu sequences were cloned, sequenced, and mapped to the human genome. A substantial portion of the cloned Alu's are located close to or within the genes that may be interesting targets for further genetic, transcription, and epigenetic studies.