Evidence is presented that temperature-sensitive Saccharomyces cerevisiae mutants, impaired in dolichol kinase (Sec59p) or dolichyl phosphate mannose synthase (Dpm1p) activity have an aberrant cell wall composition and ultrastructure. The mutants were oversensitive to Calcofluor white, an agent interacting with the cell wall chitin. In accordance with this, chemical analysis of the cell wall alkali-insoluble fraction indicated an increased amount of chitin and changes in the quantity of β1,6-and β1,3-glucan in sec59-1 and dpm1-6 mutants. In order to unravel the link between the formation of dolichyl phosphate and dolichyl phosphate mannose and the cell wall assembly, we screened a yeast genomic library for a multicopy suppressors of the thermosensitive phenotype. The RER2 and SRT1 genes, encoding cis-prenyltransferases, were isolated. In addition, the ROT1 gene, encoding protein involved in β1,6-glucan synthesis (Machi et al., 2004) and protein folding (Takeuchi et al., 2006) acted as a multicopy suppressor of the temperature-sensitive phenotype of the sec59-1 mutant. The cell wall of the mutants and of mutants bearing the multicopy suppressors was analysed for carbohydrate and mannoprotein content. We also examined the glycosylation status of the plasma membrane protein Gas1p, a β1,3-glucan elongase, and the degree of phosphorylation of the Mpk1/Slt2 protein, involved in the cell wall integrity pathway.
ABSTRACT. The sister chromatid cohesion complex of Saccharomyces cerevisiae is composed of proteins termed cohesins. The complex forms a ring structure that entraps sister DNAs, probably following replication. The mechanism of cohesion is universal and the proteins participating in this process are evolutionarily highly conserved. We investigated the Irr1p/Scc3p cohesin subunit, an under-studied protein. We show that the presence of a mutated copy of IRR1 gene, encoding the F658G substitution in Irr1p, changes the sensitivity of the heterozygous irr1-1/IRR1 diploid to cell wall-affecting compounds. Microscopic images indicate that chitin distribution in the mutant cell wall is affected, although the biochemical composition of the cell wall is not drastically changed. This observation suggests that irr1-1 mutation in heterozygous state may influence the cell wall integrity and indicates a possible link between mechanisms regulating the cell wall biosynthesis, nuclear migration and chromosome segregation.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.