Effects of cyclin-dependent kinase 9 ( CDK9) on lytic replication of Kaposi′s sarcoma-associated her-pesvirus ( KSHV) / 中华微生物学和免疫学杂志

ABSTRACT

Objective To investigate the role of cyclin-dependent kinase 9 ( CDK9) in regulating lytic replication of Kaposi′s sarcoma-associated herpesvirus ( KSHV) .Methods Percentages of red fluores-cent protein (RFP) positive cells were counted after treating and stimulating iSLK .219 cells with FIT-039, a CDK9 specific inhibitor , and doxycycline ( Dox ) , respectively , or transfecting and stimulating them with CDK9 siRNA (si-CDK9) and Dox, respectively.Quantitative real-time PCR was used to detect the expres-sion of KSHV genes at mRNA level in TREx-K-Rta BCBL-1 cells treated with FIT-039 or transfected with si-CKD9 in the presence of Dox.Chromatin immunoprecipitation (ChIP) assay was used to examine the enrich-ment of RNA polymerase Ⅱ( RNA PolⅡ) and phosphorylated CTD-S2 of RNA PolⅡon the PAN promot-er in TREx-K-Rta BCBL-1 cells treated with FIT-039.Results Both FIT-039 intervention and CDK9 knockdown dramatically deceased the percentage of RFP-positive iSLK.219 cells and suppressed the expres-sion of ORF50, PAN and K2 in TREx-K-Rta BCBL-1 cells at mRNA level.Furthermore, FIT-039 signifi-cantly inhibited the enrichment of RNA Pol Ⅱand phosphorylated CTD-S2 of RNA Pol Ⅱon the PAN pro-moter in TREx-K-Rta BCBL-1 cells.Conclusion CDK9 is involved in regulating the lytic replication of KSHV through promoting the phosphorylation of CTD-S2 of RNA Pol Ⅱ.