Northern blot analysis of TSG. (A) TSG mRNA is selectively suppressed in the presence of Tob. RNA extracted from Jurkat cells transfected with Tob cDNA or empty vector and expression of TSG was examined by Northern blot. (B) TSG mRNA is up-regulated in human CD4⁺ peripheral blood lymphocytes by mitogenic stimuli. Purified CD4⁺ T lymphocytes were cultured as indicated for 24 hours, RNA was extracted, and expression of TSG and TOB was examined by Northern blot. (C) TSG is expressed in human immune tissues. Northern blots of samples from human immune tissues were hybridized with human Tsg cDNA probe. In all experiments shown in panels A-C, after initial hybridization with Tsg probe, blots were striped and reprobed with human G3PDH cDNA probe. Relative molecular lengths, in kilobases, are indicated.