Molecular characterization of a MSRV-like sequence identified by RDA from monozygotic twin pairs discordant for schizophrenia

Retroviral-related amplicons were used in modified RDA to identify four seq uences from affected members of three pairs of monozygotic twins discordant for schizophrenia. One sequence (schizophrenia associated retrovirus, SZRV -1, GenBank Accession No. AF135487) is characterized here. It is similar to two known sequences of retroviral origin: multiple sclerosis-associated re trovirus, MSRV (GenBank Accession No. AF009668), and ERV-9 (GenBank Accessi on No. S77575). It is present in multiple copies in the human genome and ha s been localized to six different chromosomal sites. A zooblot shows that t his multicopy sequence is predominant in the primate lineage and present in rhesus monkeys and humans. SZRV-1 is expressed as a 9-kb RNA band in the p lacenta. This could offer support to the hypothesis that retroviral sequenc es transposing during fetal growth may alter neurodevelopmental genes and c ause diseases, although its direct involvement in the causation of schizoph renia remains to be established. (C) 1999 Academic Press.