ARID1B haploinsufficiency results in delayed S
Phase entry. Real Time Quantitative PCR analysis of patient-derived (Patient 1) and control (90087 and 90090) fibroblasts was performed using Taqman probes directed against ARID1B and the housekeeping control RPLO. Samples were normalised to control 90090, which was assigned a value of 1 and analysed by the Pfaffl relative quantification method. The expression of ARID1B was significantly reduced in both Patient 1 and the control 90090 after shRNAmir mediated knockdown of ARID1B (90090-KD), whereas the non-silencing control did not alter ARID1B expression (90090-NS) (A). Cell cycle dynamics of serum-starved cells undergoing S1 phase after serum replenishment was analysed using ModFit LT. The percentage of cells undergoing S1 phase at 20 hours post serum replenishment was significantly lower in both patient 1 (P = 0.0002) and 90090-KD (P = 0.005) compared to control (B).