Fig 4. CBF-1 suppresses WC-independent frq transcription by promoting the recruitment of the transcriptional co-repressor RCM-1.

(A, B) ChIP assays showing the enrichment of A) WC-1 and B) WC-2 is decreased and the peak of WC-1 binding is delayed in the cbf-1^KO strain compared to the wild-type strain. (C) The phosphorylation of WC-1 and WC-2 was markedly increased over time in the cbf-1^KO strain compared to the wild-type strain. (D) Western blot analyses were performed using antibodies against FRQ or WC-2 in the wild-type, cbf-1^KO, wc-2^KO, and cbf-1^KO wc-2^KO strains. Samples were grown under constant light (LL) or in DD for indicated hours before harvest. (E) Northern blot analyses of the levels of frq mRNA in wild-type, cbf-1^KO, wc-2^KO, and cbf-1^KO wc-2^KO strains. (F) The enrichment of RCM-1 at the C-box of frq promoter is reduced in cbf-1^KO strains at the DD14 compared to the wild-type strain. (G) The levels of RCM-1 phosphorylation of the cbf-1^KO strain are higher than those in wild-type strain at the indicated times. (H) The RCM-1 protein levels are similar to that in the cbf-1^KO and wild-type strains. The errors bars ±S.D. (n = 3; **P<0.01 and ***P<0.001; two-tailed t-test).