[Screen in Saccharomyces cerevisiae for transposon insertion sites able to rescue phenotype of MTM1 deletion mutant using mTn-lacZ/LEU2 transposon library].

OBJECTIVE

MTM1 gene is essential for superoxide dismutase 2 activity and normal mitochondrial functions. MTM1 deletion results in decreased superoxide dismutase 2 activity, impaired mitochondrial functions and growth defect on nonfermentable carbon source. To promote understanding of MTM1 gene, we started a genetic screen for transposon insertions which are able to rescue the growth defect resulting from MTM1 deletion.

METHODS

Routine screening strategy didnt work because of the irreversible damage caused by MTM1 deletion. So we adopted the following screening strategy: we transformed a plasmid overexpressing MTM1 into wild type before deleting MTM1 in chromosome and got the resulting strain, designated YES2MTM1. Then we transformed mTn-lacZ/LEU2 transposon library into the YES2MTM1 strain. Transformants lost the plasmid overexpressing MTM1 after 5-Fluoroorotic acid treatment. We picked up the yeast strains able to grow on nonfermentable carbon source with MTM1 deletion and some transposon insertion and identified the insertion sites.

RESULTS

We found transposon insertions in two genes were able to rescue the growth defect resulting from MTM1 deletion on nonfermentable carbon source.

CONCLUSION

Our study will provide reference for thorough understanding of MTM1 gene function.