Fig. 2

HOTAIR is enriched in exosome fraction of GBM serum. Exosomes were purified as previously described and the level of HOTAIR was measured by qRT-PCR. a, b Exosomes were found to be 100 nM or smaller (gray regions) in size as judged by NanoSight analysis. c Exosome-enriched protein CD63 was detected by Western blot analysis. d HOTAIR was present in whole serum and purified exosomes but not in serum supernatant depleted of exosomes. e Sequencing of HOTAIR qRT-PCR products amplified from GBM serum demonstrates the HOTAIR sequence. We amplified HOTAIR in GBM patient serum using qRT-PCR, followed by subcloning the corresponding PCR products into pCR™4-TOPO®TA vector and sequencing the inserts. We found that the inserts indeed contained HOTAIR sequence, f that it corresponds to the predicted HOTAIR sequence, and g mapped to the HOTAIR locus on the USC browser