Fig 2. HERV-K envelope protein induces expression of several transcription factors.

(A) Scheme of the experimental procedure. 293T cells were transfected with the indicated plasmids, in duplicate for each condition. 24 and 48 hours post transfection, cells were harvested for RNA extraction. Gene expression analysis was performed with the Agilent SurePrint G3 Human GE 8x60K Microarray. (B) Data from microarrays were processed and normalized as described in the material and methods in order to assess differentially expressed genes between control and HERV-K Env expressing samples. The genes listed here were from the 48 hour time point and selected by the following criteria: fold-change ≥2 and a false detection rate (FDR) <0.05. Expression levels of the top five genes were confirmed by qRT-PCR performed on the same samples. The results after normalisation with RPLO gene are indicated in the right column. (C) qRT-PCR was performed on total RNA extracted from Ampho Env (control) or HERV-K Env-Rec expressing cells at 48 hours post-transfection. The amount of mRNA transcripts for the indicated transcription factors (EGR1: Early Growth Response 1; ETV4 and ETV5: Ets variant 4/5) were normalised to the RPLO gene and expressed relative to non-transfected 293T cells. Error bars represent the standard deviation of five independent experiments. Significant differences in gene expression were assessed using a one-tailed t test performed relative to the Ampho Env condition.