FIG. 9.
Spt2 is involved in a nucleosome reassembly pathway that uses old histones at SRG1. (A) Diagram representing the different sources of histone H3 and H4 in the yeast strains used in the experiment. (B) Diagram representing the experimental procedure. (C and D) Spt2 inhibits the incorporation of new histone H3 at the SRG1 region corresponding to the SER3 promoter. Yeast cells from the wild-type (WT) (YAN1049) or spt2Δ strains (YAN1050) containing the construction encoding histone Flag-H3 under the control of the GAL1 promoter were grown in raffinose-containing medium to mid-log phase. After G1 arrest by α-factor, the cells were formaldehyde fixed or shifted to galactose medium for 60 or 120 min prior to formaldehyde treatment. ChIP assays were then performed using anti-Flag antibody. The values shown (relative IP/input) represent the averages and standard errors of results from three independent experiments. *, P < 0.05. (E) Model of SER3 regulation by ncRNA SRG1 transcription.