RESUMO
MTM1 gene is essential for SOD2 activity and normal mitochondrial function. MTM1 deletion results in decreased SOD2 activity, impaired mitochondrial function and growth defect on nonfermentable carbon source. A yeast genomic library was transformed into mtm1 deletion mutant to screen for suppressor genes of MTM1. The damage caused by MTM1 deletion is irreversible and even overexpression of MTM1 can not rescue the growth defect of mtm1 deletion mutant. Another screening strategy was adopted: a plasmid overexpressing MTM1 was transformed into wild type before the MTM1 gene on chromosome was deleted. The resulting strain, designated YES2MTM1, was transformed with a yeast genomic library. Transformants lost the plasmid overexpressing MTM1 after 5-FOA treatment. Yeast strains able to grow on nonfermentable carbon source with MTM1 deletion and overexpression of some DNA fragments were picked up and candidate suppressor genes were identified. Overexpression of five genes were identified to be able to rescue the growth defect on nonfermentable carbon source. The study will provide reference for MTM1 gene function and screening for suppressor of genes whose deletion result in irreversible damage.