Figure 5. KAP1 mediates transcriptional repression of KRAB–ZFPs.

mRNA expression levels upon stable KAP1 (shKAP1) and GFP (shGFP) knockdown were assessed through qPCR in HeLa cells. The relative quantities were measured for (A) cluster-specific KRAB–ZFP transcripts and for (B) different heterochromatin protein expression levels. β2-microglobulin was used as a normalization gene, whereas the expression of the eukaryotic elongation factor 1α (EEF1α) served as a negative control. qPCR values are expressed as means +SEM of six experiments. The statistical test conducted was a t-test with Welch's correction, which assumes unequal variances: *: p<0.05.