FIG 1.

LIGHT, but not TNF-α, markedly enhances ERVK polyprotein and RT expression in astrocytes. SVGA cells were treated with various doses of TNF-α or LIGHT for 24 h. Western blotting and confocal microscopy were used to detect alterations in ERVK RT, IRF1, and NF-κB p65, p50, and p52 protein levels. (A) Western blot (cropped) showing that LIGHT strongly induced ERVK polyprotein (125 kDa) expression and cleavage to produce the small, 52/54-kDa RT without RNase H and the larger, 60-kDa RT with RNase H, concomitantly with upregulation of IRF1 and NF-κB protein levels. In comparison, TNF-α slightly enhanced ERVK polyprotein and RT subunit expression. β-Actin was used as the loading control (n = 3). Quantification of the 54-kDa band is depicted in green. (B) Representative confocal micrographs depicting LIGHT-mediated induction of ERVK RT expression. ERVK RT aggregates were deposited proximal to the nucleus and formed a perinuclear ring (n = 3). Quantification of the ERVK RT/DAPI staining ratio is presented in each merged micrograph.