A peptide nucleic acid (PNA)-mediated polymerase chain reaction clamping allows the selective inhibition of the ERVWE1 gene amplification.

A new peptide nucleic acid (PNA) mediated QPCR technique for the detection and quantification of the Multiple Sclerosis-Associated Retrovirus (MSRV) belonging to the human endogenous retrovirus-W (HERV-W) family has been developed. The assay utilizes a PNA probe which is fully complementary to the ERVWE1 sequence, another member of the HERV-W family which is closely related to MSRV. Due to its excellent affinity to a completely matched template, PNA probe selectively blocks the amplification of ERVWE1 thus allowing the specific and exclusive detection and quantification of the MSRV as PNA does not interfere with the amplification of MSRV. Using this newly developed method we found that MSRV is predominantly expressed over ERWVE1 in astrocyte-derived U-87 MG cell line but not in human umbilical vein endothelial cells or human placental cells.