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. 2002 Jun;22(12):4136–4146. doi: 10.1128/MCB.22.12.4136-4146.2002

FIG. 3.

FIG. 3.

Life span is extended in dna2 strains with an extra copy of SIR2 or fob1Δ. (A) An extra copy of SIR2 extends dna2 life span. All strains were isogenic derivatives of A364a for the SIR2 study. Wild-type or dna2-1 cells carrying an extra copy of SIR2 were created with a plasmid from David Shore. The Xho-PstI fragment from pRS415 was cloned into the pRS404 plasmid. The resulting pRS304SIR2 plasmid was cut with SnaBI and transformed into the dna2-1 or wild-type strain. The constructs were verified by Southern blotting. (B) Deletion of FOB1 extends the maximum life span of dna2 mutants. For the fob1Δ study, strains were from the A364a background (20). Strain 7585-2-3 MATα trp1 leu2 ura3 his3 dna2-2 sol3Δ::LEU2 fob1Δ::HIS3 and the isogenic DNA2sol3Δ::LEU2 fob1Δ::HIS3 strain were constructed with a fob1Δ::HIS3-containing plasmid from M. Kobayashi (46). Similar results were obtained with respect to maximum life span in W303 DNA2, W303 dna2-2, W303 DNA2fob1Δ::HIS3, and W303 dna2-2fob1Δ::HIS3 strains, except that the fob1Δ strains had a smaller effect on the average life span of both wild-type and dna2-2 strains. Maximum life span extension by fob1Δ was similar. Strains and average and maximum life spans are further described in the text and in Table 3.