Deletion of SIR4 results in 20-25% reduction of lifespan [10521401]. SIR4 deletion mutants exhibit loss of silencing at the silent mating type loci [3297920] and telomeres [1913809] and have slightly elevated level of rDNA marker loss [10521401]. The short lifespan of a SIR4 mutant is probably due to the simultaneous expression of a and alpha mating-type information, which indirectly causes an increase in rDNA recombination and likely increases the production of extrachromosomal rDNA circles. Lifespan reduction by SIR4 deletion is suppressed by preventing mating type heterozygosity (co-expression of MATa and MATalpha).
Mean: -20 to -25
GenAge
GenDR
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