biostudies-literatureUnknown8(4)Yoo HSPAF complex (PAFc) is an RNA polymerase II associated factor that controls diverse steps of transcription. Although it is generally associated with actively transcribed genes, a repressive PAFc has also been suggested. Here, we report that PAFc regulates the transition from transcription initiation to transcription elongation. PAFc repressed IL-6-induced, but not TNF-α-induced, immediate early gene expression. PAFc constitutively associated with the 5'-coding region of the c-Fos locus, then transiently dissociated upon IL-6 stimulation. When CTR9, a component of PAFc, was depleted, higher levels of serine 5-phosphorylated or serine 2-phosphorylated forms of RNA Polymerase II were associated with the unstimulated c-Fos locus. We also observed an increased association of CDK9, a kinase compoPloS onee61055https://www.ebi.ac.uk/biostudies/studies/S-EPMC3623864biostudies-literatureCTR9, a component of PAF complex, controls elongation block at the c-Fos locus via signal-dependent regulation of chromatin-bound NELF dissociation.PMC3623864Seo JHYoo JYYoo HSfalseCTR9, a component of PAF complex, controls elongation block at the c-Fos locus via signal-dependent regulation of chromatin-bound NELF dissociation.PAF complex (PAFc) is an RNA polymerase II associated factor that controls diverse steps of transcription. Although it is generally associated with actively transcribed genes, a repressive PAFc has also been suggested. Here, we report that PAFc regulates the transition from transcription initiation to transcription elongation. PAFc repressed IL-6-induced, but not TNF-α-induced, immediate early gene expression. PAFc constitutively associated with the 5'-coding region of the c-Fos locus, then transiently dissociated upon IL-6 stimulation. When CTR9, a component of PAFc, was depleted, higher levels of serine 5-phosphorylated or serine 2-phosphorylated forms of RNA Polymerase II were associated with the unstimulated c-Fos locus. We also observed an increased association of CDK9, a kinase compo2013-01-01T00:00:00Z20132025-04-26T21:07:08.635Z2019-03-26T23:14:06ZS-EPMC36238642359338810.1371/journal.pone.0061055