Relative quantification of specific HERV-W transcript levels.

<p>Lesion (A) and non-malignant (B) cDNAs from each patient (patients 1-8, 12, representing stages III, IA, IVA, fMF, fMF, IB, IA, IB, IB, in respective order) were amplified using HERV-W specific primers (targeting a region within the <i>pol</i> gene) and normalized with housekeeping gene RNA polymerase II. Lesion samples are depicted by dark grey bars, non-malignant intact skin samples by light gray bars. No data in patient1B and patient 2B means there was no detectable transcription. Relative mRNA expression levels are given as mean ±SD. Statistical significance is presented as *p<0.05, **p>0.02, and ***p<0.01. Concordance between the microarray and qRT-PCR data is not complete due to the differences in primer specificities (see Methods). fMF= folliculotrophic MF.</p

Relative expression of <i>ERVWE1</i> mRNA in MF skin tissue.

<p><i>ERVWE1</i> expression was detected in 3/7 MF lesions analysed by Taqman qPCR. Patients 3 and 7 were also analysed, but the MF lesions showed no <i>ERVWE1</i> expression (Figure S1). Patients 7 and 18 showed expression also in the clinically healthy (H), non-lesional skin samples (the data of patient 7 in Figure S1). <i>GAPDH</i> served as internal standard and was expressed in every sample (see Methods for more details). MF patients 18 and 19 were collected afterwards and were therefore not included in other experiments. See detailed amplification curves in Figure S1.</p

Syncytin-1 protein expression is found in MF skin lesions but not in lichen planus.

<p>A) Morphologically malignant lymphocytes within Pautrier’s microabscesses (invading the epidermis) stained positive (red arrow) for Syncytin-1 in immunohistochemistry, DAB 40x B) same sample as in a) but with NovaRED as a chromogen, 100x, C) same sample as in A) without primary antibody, DAB 40x, D) Lichen ruber planus sample with no Syncytin-1 expression albeit abundant numbers of inflammatory T cells, NovaRED 20x, E) in folliculotropic MF, Syncytin-1-positive lymphocytes protruding in the hair follicle, 20x and F) human placenta as a positive control, 20x. Scale bar is 20µm.</p

Retroarray analysis of HERV transcriptional activity in MF.

<p>HERV activity profiles representing pairs of lesion (A) and non-malignant (B) skin tissue specimens (digitally aligned). Each sample pair (n=17) was derived from an individual patient (MF 1-12, psoriasis 13-17). HERV subgroups representing a skin-specific core transcription profile (HERV-E, HERV-F, HERV-W, ERV-9, HERV-K(HML-4)) are emphasized with red letters. A panel of housekeeping genes (Ubiquitin, GAPDH, RPL19, β-Actin, HPRT) served as internal controls (for detailed information on methodology, see [77,79]). Each positive spot on the microarray may represent multiple HERV loci of one subgroup of multicopy HERV elements with sufficient sequence similarity that individual elements cannot be distinguished. Weak signals may be unrecognizable in the printed figure.</p

Transcriptional activity of HERV-W proviral loci in lesion and non-malignant skin tissue with MF.

<p>HERV-W transcripts were amplified using HERV-W <i>env</i> derived primers, cloned, sequenced and assigned to proviral loci as described previously [59]. For each proviral locus the relative cloning frequency is given as % of the total number of analyzed clones per skin tissue. HERV-W loci 6q21 and 7q21, 2 showed the highest relative cloning frequency, thus relative transcript levels in MF-lesions.</p