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. Author manuscript; available in PMC: 2015 Oct 23.
Published in final edited form as: Cell. 2014 Oct 23;159(3):499–513. doi: 10.1016/j.cell.2014.09.051

Figure 4. STAT1 enhances the transcriptional response to juxtacrine NOTCH3 signaling that is required for stroma-mediated protection.

Figure 4

A) Cell death of 1833 IRDS-R in co-culture after RT. MRC5 fibroblasts were separated by a transwell filter large enough to allow exosome passage (n=3). B) Immunoblot of the indicated NOTCH family members in 1833 IRDS-R after mono-culture (M) or co-culture (C). Arrow indicates cleaved intracellular domain. C) Expression of NOTCH target genes in IRDS-R and IRDS-NR after co-culture, and D) after STAT1 knockdown in 1833 IRDS-R after co-culture. Notch targets were experimentally defined by GSI washout (Table S4) and used in Gene Set Analysis. E) Expression of the indicated NOTCH target gene primary transcript (PT) in 1833 IRDS-R (n=3). F) Expression of HEY1 PT in response to doxcycyline (Dox) induced NICD3 in 1833 IRDS-R with or without addition of co-culture CM (mean ± SEM, n=6–8). Inset shows NICD3 levels after Dox addition (µg/ml). G) Expression of the indicated primary transcripts to NICD3 after addition of co-culture CM or CM depleted of exosomes (Exo dep). CM compared to CM depleted of exosomes is used for significance levels (mean ± SEM, n=4–6). H) ENCODE ChIP data for STAT1 occupancy of the HEY1 proximal promoter region is shown along the indicated genomic coordinates. Bar plots show STAT1 ChIP from 1833 IRDS-R with and without addition of CM (left) and after mono- or co-culture (right). Relative position upstream of the transcriptional start site (TSS) is labeled on the x-axis for each bar plot. Shown are two representative experiments (mean ± SD) out of four total. I) Expression of HEY1 and HES1 mRNA or primary transcripts in response to NICD3 and co-culture CM in 1833 IRDS-R with and without STAT1 knockdown (mean ± SEM, n=4–7). ●p<0.10, *p < 0.05. See Figure S4.