Table 1. Strains used in this study.

Strain	Genetic Background	Genotype	Related Figures
DLY640	W303	MATa	Figure 4, and Figure S1 and Figure S3 in File S1
DLY1195	W303	MATα cdc13-1	Figure 4
DLY1255	W303	MATa rad9::HIS3 cdc13-1	Figure S2 in File S1
DLY1256	W303	MATα rad9::HIS3 cdc13-1	Figure S2 in File S1
DLY1273	W303	MATa exo1::LEU2	Figure 5
DLY1296	W303	MATa exo1::LEU2 cdc13-1	Figure 4
DLY1543	W303	MATa tel1::TRP1 cdc13-1	Figure S3 in File S1
DLY1544	W303	MATα tel1::TRP1 cdc13-1	Figure S3 in File S1
DLY1585	W303	MATα rad9::KANMX	Figure S1 in File S1
DLY2234	W303	MATa rad9::LEU2	S1 and S2 in File S1
DLY2787	W303	MATα yku70::LEU2	Figure 4
DLY2988	W303	MATa cdc13-1 rad53::HIS3 sml1::KANMX	Figure 5
DLY3001	W303	MATα	Figure S1 and Figure S2 in File S1
DLY4528	W303	MATa nmd2::HIS3	Figure S1 in File S1
DLY4557	W303	MATa cdc13-1 int	Figure 5
DLY4625	W303	MATa cdc13-1 int nmd2::HIS3	Figure 4
DLY4647	W303	MATa cdc13-1 rad9::HIS3	Figure 5 and Figure S3 in File S1
DLY4921	W303	MATa cdc13-1 int exo1::LEU2	Figure 5
DLY4922	W303	MATa cdc13-1 rad9::HIS3 exo1::LEU2	Figure 5
DLY4931	W303	MATα cdc13-1 rad24::TRP1	Figure 5
DLY5007	W303	MATα yku70::LEU2 nmd2::HIS3	Figure 4
DLY5097	W303	MATa cdc13-1 exo1::LEU2 rad24::TRP1	Figure 5
DLY5255	W303	MATα rad9::LEU2 nmd2::HIS3 cdc13-1 int	Figure 4
DLY5260	W303	MATa cdc13-1 cdc15-2 bar1::hisG	Figure 6
DLY5261	W303	MATa cdc13-1 cdc15-2 bar1::hisG	Figure 6
DLY5266	W303	MATa cdc13-1 cdc15-2 bar1::hisG exo1::LEU2	Figure 6
DLY5386	S288C	MATα LEU2::cdc13-1 int::HPHMX rad9::NATMX lyp1∆ can1::MFA1pr-HIS3 ura3 leu2 his3 LYS2+	Figure 2 and Figure S4 in File S1
DLY5688	S288C	MATα LEU2::cdc13-1 int::HPHMX lyp1∆ can1::MFA1pr-HIS3 ura3 leu2 his3 LYS2+	Figure 1, Figure 2, and Figure S4 in File S1
DLY6720	S288C	MATα LEU2::cdc13-1 int::HPHMX exo1::NATMX lyp1∆ can1::STE2pr-his5 ura3 leu2 his3 LYS2+	Figure 2 and Figure S4 in File S1
DLY7106	W303	MATa chk1::HIS3	Figure 5
DLY7108	W303	MATa exo2::LEU2 chk1::HIS3	Figure 5
DLY7110	W303	MATa cdc13-1 chk1::HIS3	Figure 5
DLY7112	W303	MATa cdc13-1 exo1::LEU2 chk1::HIS3	Figure 5
DLY7143	W303	MATa cdc13-1 cdc15-2 bar1::hisG chk1::HIS3	Figure 6
DLY7145	W303	MATa cdc13-1 cdc15-2 bar1::hisG exo1::LEU2 chk1::HIS3	Figure 6
DLY7146	W303	MATa cdc13-1 cdc15-2 bar1::hisG exo1::LEU2 chk1::HIS3	Figure 6
DLY7747	W303	MATa exo1::LEU2 nmd2::URA3 cdc13-1	Figure 4
DLY8460	W303	MATa	Figure 5
DLY8767	S288C	MATα LEU2::stn1-13::HPHMX lyp1::NATMX can1::STE2pr-his5 ura3 leu2 his3 met15 LYS2+	Figure 1
DLY9181	S288C	MATα LEU2::rfa3-313::HPHMX lyp1::NATMX can1::STE2pr-his5 ura3 leu2 his3 met15 LYS2+	Figure 1
DLY9326	S288C	MATα lyp1::HPHMX::LEU2::NATMX can1::STE2pr-his5 ura3 leu2 his3 met15 LYS2+	Figure 1
DLY9866	W303	MATa rad9::LEU2 cdc13-1	Figure 4 and S3 in File S1
DLY11098	W303	MATα stn1-13	Figure S1 in File S1
DLY11099	W303	MATα stn1-13	Figure S1 in File S1
DLY11100	W303	MATα stn1-13 rad9::LEU2	Figure S1 in File S1
DLY11101	W303	MATa stn1-13 rad9::LEU2	Figure S1 in File S1
DLY11102	W303	MATα stn1-13 rad24::TRP1	Figure S1 in File S1
DLY11103	W303	MATa stn1-13 rad24::TRP1	Figure S1 in File S1
DLY11104	W303	MATa stn1-13 rad17::TRP1	Figure S1 in File S1
DLY11105	W303	MATα stn1-13 rad17::TRP1	Figure S1 in File S1
DLY11215	W303	MATα nmd2::URA3 stn1-13	Figure 4
DLY11216	W303	MATa stn1-13	Figure 4
DLY11637	W303	MATa rfa3-313::KANMX	Figure S2 in File S1
DLY11696	W303	MATa rfa3-313::KANMX nmd2::HIS3	Figure S2 in File S1
DLY11697	W303	MATα rfa3-313::KANMX nmd2::HIS3	Figure S2 in File S1
DLY11729	W303	MATα rfa3-313::KANMX rad9::HIS3	Figure S2 in File S1
DLY11730	W303	MATα rfa3-313::KANMX rad9::HIS3	Figure S2 in File S1
DLY11182	W303	Matα rad9::HIS3 tel1::TRP1 cdc13-1	Figure S3 in File S1
DLY11183	W303	Mata rad9::HIS3 tel1::TRP1 cdc13-1	Figure S3 in File S1