Transcriptome Analysis of HERV-V3 Expression

The cDNA synthesis and amplification steps were performed using 16 ng of RNA with the Ovation Pico WTA System V2 kit (Nugen) according to the manufacturer’s instructions. Five micrograms of amplified purified DNA were fragmented into 50–200 bp fragments and were 3-labeled using the Encore Biotin Module kit (Nugen) according to the manufacturer’s instructions. The HERV-V3 microarrays were hybridised at 50 °C for 18 h in an oven with constant stirring (60 rpm). Washing and staining were carried out according to the protocol provided by the manufacturer, using the GeneChip fluidics station 450 (Affymetrix). The arrays were finally scanned using the GeneChip scanner 3000 7G (Affymetrix) fluorometric scanner. Images (DAT files) were converted to CEL files using GCOS software (Affymetrix) [30 (link)]. The experimental data generated have been filed with the National Center for Biotechnology Information (NCBI) and are available on the GEO DataSets site under access number GSE108239.