Loss of CASP8AP2 / FLASH function induces changes in the expression of the replication dependent histone genes. (A) The CASP8AP2/FLASH RNAi signature was subjected to gene set enrichment analysis for 79 annotated human histone genes. A very high positive correlation was observed indicating a significant enrichment (Normalized enrichment score = 2.53; FDR q-value < 0.001) for deregulation of transcript levels of the human histone genes following silencing of CASP8AP2/FLASH. (B) Diagrammatic representation of the two annotated transcript variants of HIST1H2BD and the relative positions of PCR primers used in this study. The primers for the HIST1H2BD variant, NM_138720, were designed to flank a known splice site within this transcript so is its expression could be assessed by qRT-PCR without the risk of amplifying genomic DNA. (C) RT-PCR quantification of changes in (i) CASP8AP2/FLASH and (ii) HIST1H2BD expression using cDNA generated using random hexamer priming. (D) RT-PCR quantification of changes in CASP8AP2/FLASH and HIST1H2BD expression following silencing of CASP8AP2/FLASH. RNA was harvested 72 hours after silencing of CASP8AP2/FLASH and cDNA generated using either (i) random hexamers or (ii) oligo dT. Data is shown as the median of two independent cDNA syntheses and two independent PCR reactions per cDNA synthesis.