Fig. 2
From: Unphosphorylated STAT3 in heterochromatin formation and tumor suppression in lung cancer
uSTAT3 promotes heterochromatin formation in lung cancer cells. (a) Total lysates of A549 cells stably transfected with the indicated DNA constructs were subjected to SDS-PAGE and blotted with anti-H3K9me3. Note that expressing STAT3Y705F or shSTAT3 dramatically increased or moderately decreased H3K9me3 levels, respectively. sh: small hairpin RNAi; NC, non-targeting control. (b) A549 cells were transiently transfected with MyC-tagged STAT3Y705F (upper) or STAT3V462A (lower) were immunostained with anti-H3K9me3 (left) or Myc (middle). Note that STAT3Y705F, but not STAT3V462A, expression increased H3K9me3, when compared with untransfected neighboring cells. (c,d) A549 cells stably expressing the indicated STAT3 or HP1α transgenes were transfected with a heterochromatin FRET sensor, consisting of an HP1-H3 peptide with CFP and YFP. (c) Representative FRET images of cells with indicated transgene expression. (d) Mean FRET efficiency (YFP/CFP fluorescence ratio) with standard deviations was calculated for each group. * indicates p < 0.05 in Student’s t-test. Scale bars, 2 μm