FIG 5.

RBP-Jκ is involved in hypoxia-induced transcription of KSHV lytic genes. (A) Quantitative PCR of transcriptional levels of HRE-containing viral genes from BC3 cells induction by hypoxia or TPA-NaB at different time points. The viral genes within the four hypoxia-responsive clusters (HRC) are presented at the top. The gene promoters containing HRE with an RTA (RtaBS) or RBP-Jκ (RBS) binding site are individually indicated by squares and circles. The relative ratio of each gene stimulated by hypoxia (H) and TPA-NaB (TB) was calculated as average value of induction at three time points. R/L, ratio of RTA with LANA. (B) ChIP assay of the HRE or HRE+RBS (RBP-Jκ binding site)-containing promoter. Chromatin DNA prepared from KSHV-positive cell line BC3 with 21% (−) or 1% oxygen (O₂) treatment overnight before harvest was subjected to ChIP assays by antibodies as indicated. The DNA binding level of each protein was detected by qPCR, and the results are presented as percentages compared with input. Asterisks indicate P values as follows: *, P > 0.05, and **, P < 0.01.