FIG. 5.

The SIR silencing complex is required for the lethal phenotype of the histone H3 K4,36,79R mutant. (A) The growth of histone H3 K4,36,79R mutant strains lacking SIR2, SIR3, SIR4, or RPD3 was tested on SC-ADE plates with or without 5-FOA, as shown in Fig. 1A. (B) A schematic representation of the chromosome V-L telomere (TEL V-L) region. The location of the Y′ element, coding sequences, and ChIP primer pairs are depicted. (C and D) Increased binding by the SIR silencing complex near the chromosome V-L telomere region. The abundances of Sir4 at the TEL V-L region in wild-type strains and H3 mutants (and an untagged strain as control) were determined by ChIP analysis. The Sir4 binding ratio is shown as the ratio of each primer pair to the ACT1 primer pair. Each error bar represents the standard deviation of three independent experiments. Similar results were obtained with ChIP analysis of Sir2 (see Fig. S3 in the supplemental material).