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. 2018 Jan 5;208(3):963–976. doi: 10.1534/genetics.117.300529

Figure 4.

Figure 4

High levels of transcription of the repeat reduce the requirement for Isw1 in repeat maintenance. (A) Inducible YAC construct CAG-100 pGAL1 URA3-YAC contains the pGAL1 promoter next to the CAG repeat and a transcription terminator (Tcyc1) after URA3 to terminate URA3 transcription. Locations of PCR amplicons next to the CAG repeat and URA3 used in quantitative RT-PCR (qRT-PCR) are indicated. (B) qRT-PCR analysis of CAG transcript level in wild-type (WT) and isw1∆ strains in noninducing (glucose) and inducing (galactose) conditions. CAG transcript level is normalized to the level of URA3 transcript and is presented as percent of URA3 transcript level. (C) The frequency of CAG-100 expansions was measured in WT and isw1∆ strains in noninducing (glucose) and inducing (galactose) conditions. (D) RNA polymerase II (RNAPII) occupancy next to the CAG repeat and within URA3 on the YAC was measured by RNAPII chromatin immunoprecipitation, followed by quantitative PCR in WT and isw1∆ strains in noninducing (glucose) and inducing (galactose) conditions. RNAPII immunoprecipitated is shown as % immunoprecipitated (IP)/INPUT; the average of three experiments with SEM is shown.