Figure 3.

EWSR1-FLI1 binds a GGAA-microsatellite located into the FEZF1 gene, and the number of GGAA-repeats correlates with FEZF1 expression levels. (A) The genomic region corresponding to FEZF1 and FEZF1-AS1 genes is shown (UCSC genome browser). The location of GGAA-microsatellite and its corresponding sequence is shown at the bottom of the figure. Publicly available ChIP-seq data demonstrate the binding of EWSR1-FLI1 to GGAA-microsatellite in two different Ewing sarcoma cell lines (A673 and SK-N-MC). H3K27ac ChIP-seq marks indicate that this site is transcriptionally active when EWSR1-FLI1 is bound to the GGAA-microsatellite, but not when EWSR1-FLI1 is knocked-down. (B) The length of GGAA-microsatellite was determined by PCR and fluorescent fragment analysis. Mean allele length correlates with FEZF1 mRNA expression levels (for this analysis, CADO-ES1 was excluded). (C) Correlation of FEZF1 and FEZF1-AS1 mRNA expression levels in Ewing sarcoma cells.