Fig. 6

Ibd1 is localized to actively transcribed genes. a Ibd1 occupancy. Ibd1 shows occupancy for 837 ORF and 396 intergenic regions. When Ibd1 was enriched (IP/INPUT) 2–3 (≥ 2), 4–5 (≥ 4), 6–8 (≥ 6) and more than 8 (≥ 8) times it was found in 795, 370, 69 and 19 sites, respectively, b Tetrahymena’s expression distribution and Ibd1 localization. Left panel. 9% of Tetrahymena’s genes are highly expressed. Right panel. 457 ORF (54%) that are occupied by Ibd1 are highly expressed. Ibd1 also localizes to 132 (14%) coding regions that do not present available data for the RNA-Seq data (GEO accession GSM692081 [43]); c Ibd1 prefers highly expressed genes. High amounts of Ibd1 occupancy are related to highly expressed genes. The trend shows that the higher the Ibd1 fold enrichment (IP/INPUT) is the higher the occupancy of highly expressed genes. This is evident when Ibd1 is enriched more than 4 times; d Ibd1 frequently localizes to housekeeping genes. The GO terms of the observed genes with a significant enrichment (≥ 4) are genes responsible for cell maintenance, e Tetrahymena’s GO terms. Distribution of T. thermophila genes based on GO biological functions, f ChIP-qPCR validation. Anti-FLAG ChIP was performed in the 3 replicas of untagged and 4 replicas of Ibd1-FZZ during vegetative growth. ChIP DNA was amplified using primers to amplify HTA3, RPS22, HFF1 and PDD1 by real-time PCR using SYBR green. The significant p values from the t test are represented by a * (p value < 0.05). These significant p values are 0.043 for HTA3, 0.041 for RPS22 and 0.015 for HFF1; this confirmed enrichment of Ibd1 in these genes. Our negative control, Pdd1, shows no significant p value (ns) meaning no enrichment at this gene. The error bars represent the standard error of the mean for each sample (see Additional file 8 for Raw Data)