QUALITATIVE ASSESSMENT OF RETROVIRAL ACTIVITY IN HUMAN BRAIN AND TISSUES

high throughput method for the investigation of retroviral activity in

biological samples.  The qualitative assay allows detection as well as

identification of most known retroviral reverse transcriptase (RT) – related

nucleic acids and combines multiplex polymerase chain reaction (PCR) using

disease-relevant human endogenous retroviruses (HERV) we have been investigating

the activity of HERV elements in human brain and other tissue samples. 

Employing the microarray hybridization RNA samples derived from a panel of

various human tissues (n=17) were tested for RT-related transcripts

representative for almost all known HERV families of the human genome.  Qualitative

evaluation of chip hybridization signals revealed distinct HERV activity in the

human tissues under investigation suggesting that HERV elements are active in

human cells in a tissue-specific manner. In human brain samples (cortex)

transcripts of HERV-K superfamily members, HERV-W, HERV-R, HERV-F, ERV9, and

HERV-E were observed.  Differences in the HERV activity profiles observed

between the brain sample of an unaffected control person and an untreated

patient with acute-onset schizophrenia point to the possibility that some HERV

elements may be differentially regulated in neurological disorders.  It is

not clear yet, whether the observed HERV activity variations reflect

inter-individual differences due to a different genetic background or are

specifically related with the disease.  Further investigations focusing on

the analysis of tissue samples derived from different brain regions of patients

with schizophrenia, bipolar disorders as well as matched unaffected controls,