Figure 3.

Checkpoint kinases Mec1p and Rad53p are required for DDR-induced respiration. A, C, and D, cellular oxygen consumption rates; B, cellular ATP levels in the indicated strains. A, cells were grown in YPD medium, and cellular oxygen consumption was determined in the wildtype (WT, W303-1a), rad52Δ (LG731), tel1Δ (SN159), rad52Δtel1Δ (SN158), mec1Δsml1Δ (SN120), mec1Δcrt1Δ (SN125), chk1Δ (SN136), rad52Δchk1Δ (SN138), rad53Δsml1Δ (LG606), rad53Δcrt1Δ (LG716), rad52Δrad53Δsml1Δ (PB026), rad52Δrad53Δcrt1Δ (PB019), dun1Δ (PB119), rad52Δdun1Δ (PB127), sml1Δ (LG603), and crt1Δ (LG706) cells. B, cells were grown in YPD medium, and cellular ATP levels were determined in the wildtype (WT, W303-1a), rad52Δ (LG731), rad53Δsml1Δ (LG606), rad53Δcrt1Δ (LG716), rad52Δrad53Δsml1Δ (PB026), and rad52Δrad53Δcrt1Δ (PB019) cells. A and B, values that are statistically significantly different (p < 0.05) from each other are indicated by a bracket and an asterisk. C, cells were grown in YPD medium with or without 0.1 μg/ml bleocin, and the cellular oxygen consumption was determined in the WT (W303-1a), tel1Δ (SN159), mec1Δsml1Δ (SN120), mec1Δcrt1Δ (SN125), chk1Δ (SN136), rad53Δsml1Δ (LG606), rad53Δcrt1Δ (LG716), and dun1Δ (PB119) cells. Values that are statistically significantly different (p < 0.05) from the corresponding strain grown in the absence of bleocin are indicated by an asterisk. D, cell cycle arrest of wildtype (WT, W303-1a) and rad52Δ (LG731) cells with α-factor does not affect oxygen consumption. The oxygen consumption of asynchronous and α-factor–treated cells was compared. The α-factor treatment resulted in G₁ arrest of more than 90% cells as unbudded cells. A–D, experiments were repeated three times, and the results are shown as means ± S.D. The results are expressed relative to the value for the WT strain.