Dbf2p, but not Dbf20p, associates with SWI5 and CLB2 mRNA during transcription and regulates their mRNA stability. (A) RNA immunoprecipitation of SWI5 and CLB2 mRNAs with Dbf2p-TAP and Dbf20p-TAP from mitotic cells. Binding relative to Pab1p-TAP is shown. Significant enrichment relative to untagged cells is indicated (t-test; * p<0.05 and ** p<0.01). (B) The positions of PCR amplicons used in A–E for each gene are depicted (). (C–E) Dbf2p-TAP, Dbf20p-TAP and an untagged control were immunopurified from S phase (black bars) or mitotic cells (red bars). Association of these proteins to various regions of SWI5, CLB2, ACT1, and DOA1 genes was analyzed by qPCR. Data are represented as relative to binding to TEL V, a telomeric region in Chromosome V. In each panel, an average of three experiments with the SEM is shown. Significant enrichment relative to the S phase cells is indicated (t-test; * p<0.05). (F–I) Dbf2p and Dbf20p deletions affect SWI5 and CLB2 mRNA stability. Black circles: N +/− SEM, red circles: m +/− SEM, black line: mathematical fit to N, red line: mathematical fit to m. (F) SWI5 in ΔDBF2: T of 66 s, pre-mitotic t1/2 = 4.3 min and a mitotic t1/2 =2.8 min (χ2 = 6.3) (G) SWI5 in ΔDBF20: T of 66 s, pre-mitotic t1/2 =7.1 min and a mitotic t1/2 =2.6 min (χ2 = 18.9) (H) CLB2 in ΔDBF2: T of 63 s, pre-mitotic t1/2 = 4.4 min and mitotic t1/2 =3.4 min (χ2 =115.7) (I) CLB2 in ΔDBF20: T of 63 s, pre-mitotic t1/2 =7.8 min and a mitotic t1/2 =2.2 min (χ2 = 40.3). In all graphs the x axis delineates duration of each cell cycle phase (min). M includes P/M; ANA and T/C. See also .