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Increased endocytosis in the Saccharomyces cerevisiae fragile mutant VY1160
Author(s) -
Waltschewa L.,
Kotyk A.,
Venkov P.
Publication year - 1991
Publication title -
yeast
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.923
H-Index - 102
eISSN - 1097-0061
pISSN - 0749-503X
DOI - 10.1002/yea.320070303
Subject(s) - endocytosis , internalization , biology , mutant , saccharomyces cerevisiae , wild type , microbiology and biotechnology , lucifer yellow , cell , biochemistry , yeast , intracellular , gap junction , gene
The VY1160 mutant is characterized by cell lysis in hypotonic solutions and generally increased permeability to substances for which Saccharomyces cerevisiae cells are not permeable. Two mutations, srb1 and ts1 , have been identified in VY1160 mutant, and previous studies (Kozhina et al. , 1979) have shown srb1 to be responsible for cell lysis. We now present evidence that the ts1 mutation leads to increased endocytosis in VY1160 cells. The internalization of lucifer yellow carbohydrazide in VY1160 cells is time‐, temperature‐ and energy‐dependent an consistent with a fluid‐phase mechanism of endocytosis. The rate of steady‐state accumulation of hte dye at 37°C is 145 ng/μg DNA per h for VY1160 mutant and 23 ng/μg DNA per h for S288C parental strain. Studies with isogenic strains having either the srb1 or the ts1 mutation, or SRB1 TS1 wild‐type alleles have shown that only ts1 strains possess increased endocytosis. Quantitation of endocytosis in cells grown at 24°C and shifted at 38°C shows that ts1 strains, but not srb1 and wild‐type strains, increase ten‐fold the internalization of lucifer yellow 2 h after the shift at 38°C. The analysis of ts1 × wild‐type crosses provides evidence that the temperature‐sensitive phenotype segregates together with the enhanced endocytosis. It is concluded that the increased endocytosis might the generally increased permeability of VY1160 mutant cells.