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Updated: Jan 31, 2026
A Suppressor Screen for the Characterization of Genetic Links Regulating Chronological Lifespan in Saccharomyces cerevisiae
Published on: September 17, 2020
Suppressor analysis of the mpt5/htr1/uth4/puf5 deletion in Saccharomyces cerevisiae
Kentaro Ohkuni1, Yoshiko Kikuchi, Kazuhiro Hara
1Division of Molecular Mycology and Medicine, Center for Neurological Disease and Cancer, Graduate School of Medicine, Nagoya University, 466-8550 Nagoya, Japan.
Abstract:
The MPT5/HTR1/UTH4/PUF5 gene encodes an RNA-binding Puf-family protein in Saccharomyces cerevisiae. The Deltampt5 cells exhibit pleiotropic phenotypes, including the G2/M arrest of the cell cycle and weakened cell wall at high temperatures. The Deltampt5 disruptant was also hydroxyurea (HU) sensitive. In this study we screened deletion suppressors to rescue the temperature sensitivity of Deltampt5, and identified dsf1 (YEL070W), dsf2 (YBR007C), sir2, sir3, sir4 and swe1. Multicopy suppressors identified were PKC1 and its upstream genes, but not the downstream MAPK cascade genes. The overexpression of PKC1, however, did not suppress the HU sensitivity of Deltampt5. In contrast, both the HU- and temperature-sensitivities of a-type Deltampt5 cells were suppressed by each sir deletion or a multicopy of MATalpha2, suggesting that a diploid-type expression is involved. We found that a diploid-specific IME4 gene encoding an RNA-modifying protein was responsible for the suppression of the temperature sensitivity, but not of the HU sensitivity. Furthermore, the suppression of the HU sensitivity depended on PUF4, another Puf-family gene, and overexpression of PUF4 suppressed only the HU sensitivity of Deltampt5. The protein level of Puf4 was not affected by the sir mutation. Thus, these Ime4 and Puf4 proteins play complementary roles to rescue the defects in Deltampt5 Deltasir cells.
Insights
Deletion suppressors, including SIR genes and IME4, partially rescue MPT5 deletion phenotypes in yeast. Puf4 complements SIR deletions, suggesting complementary roles for Ime4 and Puf4 in MPT5 function.
Area of Science:
- Molecular Biology
- Yeast Genetics
- Cell Cycle Regulation
Background:
- The MPT5 gene in Saccharomyces cerevisiae encodes an RNA-binding protein crucial for cell cycle progression and cell wall integrity.
- Mpt5-deficient (Deltampt5) cells display G2/M cell cycle arrest and temperature-sensitive phenotypes, along with hydroxyurea (HU) sensitivity.
Purpose of the Study:
- To identify genetic suppressors that rescue the temperature sensitivity of Deltampt5 yeast cells.
- To elucidate the roles of identified suppressors in cellular processes affected by MPT5 deletion.
Main Methods:
- Screening for deletion suppressors of Deltampt5 temperature sensitivity.
- Investigating the effects of multicopy suppressors and gene deletions on Deltampt5 phenotypes.
- Analyzing the impact of diploid-specific gene expression on Deltampt5 sensitivities.
Main Results:
- Deletion suppressors including dsf1, dsf2, SIR2, SIR3, SIR4, and SWE1 were identified.
- Overexpression of PKC1 and its upstream genes suppressed temperature sensitivity, but not HU sensitivity.
- SIR deletions and MATalpha2 suppressed both temperature and HU sensitivities in a-type Deltampt5 cells.
- The diploid-specific IME4 gene suppressed temperature sensitivity, while PUF4 suppressed HU sensitivity.
- Ime4 and Puf4 proteins exhibit complementary roles in rescuing Deltampt5 defects.
Conclusions:
- Genetic interactions reveal complex regulatory pathways involving MPT5.
- IME4 and PUF4 play distinct but complementary roles in mitigating MPT5 deletion phenotypes.
- Diploid-specific gene expression contributes to the suppression of MPT5-related cellular defects.
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