Chitin synthase III is essential for the increase in chitin level and for cell integrity in cells lacking Gas1p, a beta(1,3)-glucanosyltransferase. In order to discover whether the upregulation of chitin synthesis proceeds through the canonical transport and activation pathway of Chs3p or through an alternative one, here we studied the effects of the inactivation of the GAS1 and CHS4-5-6-7 genes. All the double-null mutants showed a temperature-sensitive cell lysis phenotype that could be suppressed by the presence of an osmotic stabilizer. In liquid YEPD at 30degreesC, chs4Delta gas1Delta, chs5Delta gas1Delta, chs6Deltagas1Delta and chs7Deltagas1Delta mutants were unable to grow, whereas they grew very slowly in minimal medium and showed low viability. High osmolarity suppressed the defective phenotype and restored growth. In chs4 gas1, chs5 gas1 and chs7 gas1, chitin levels did not increase and were reduced to only 10%, while in chs6 gas1 the value of gas1 was reduced to 20-40%. To investigate at which level the upregulation of chitin synthesis could occur, mRNA levels were monitored. The expression of CHS4-5-6-7 did not change significantly in gas1A. In strains expressing HA-tagged forms, the localization of Chs3p and Chs5p was examined. In the gas1 mutant the fluorescence pattern was affected and the proteins appeared abnormally present in the bud. The results indicate that: (a) the function of the CHS4-7 genes is required for chitin hyperaccumulation in gas1 mutant and for cell integrity; (b) homologous genes do not replace their function; (c) the regulation of CHS4-7 genes does not occur at transcriptional level. Control of the position of chitin synthesis could be important in protecting the bud from lysis.

Maintenance of cell integrity in the gas1 mutant of Saccharomyces cerevisiae requires the Chs3p-targeting and activation pathway and involves an unusual Chs3p localization / C. Carotti, L. Ferrario, C. Roncero, M.-H. Valdivieso, A. Duran, L. Popolo. - In: YEAST. - ISSN 0749-503X. - 19:13(2002 Sep 30), pp. 1113-1124.

Maintenance of cell integrity in the gas1 mutant of Saccharomyces cerevisiae requires the Chs3p-targeting and activation pathway and involves an unusual Chs3p localization

C. Carotti
Primo
;
L. Popolo
Ultimo
2002

Abstract

Chitin synthase III is essential for the increase in chitin level and for cell integrity in cells lacking Gas1p, a beta(1,3)-glucanosyltransferase. In order to discover whether the upregulation of chitin synthesis proceeds through the canonical transport and activation pathway of Chs3p or through an alternative one, here we studied the effects of the inactivation of the GAS1 and CHS4-5-6-7 genes. All the double-null mutants showed a temperature-sensitive cell lysis phenotype that could be suppressed by the presence of an osmotic stabilizer. In liquid YEPD at 30degreesC, chs4Delta gas1Delta, chs5Delta gas1Delta, chs6Deltagas1Delta and chs7Deltagas1Delta mutants were unable to grow, whereas they grew very slowly in minimal medium and showed low viability. High osmolarity suppressed the defective phenotype and restored growth. In chs4 gas1, chs5 gas1 and chs7 gas1, chitin levels did not increase and were reduced to only 10%, while in chs6 gas1 the value of gas1 was reduced to 20-40%. To investigate at which level the upregulation of chitin synthesis could occur, mRNA levels were monitored. The expression of CHS4-5-6-7 did not change significantly in gas1A. In strains expressing HA-tagged forms, the localization of Chs3p and Chs5p was examined. In the gas1 mutant the fluorescence pattern was affected and the proteins appeared abnormally present in the bud. The results indicate that: (a) the function of the CHS4-7 genes is required for chitin hyperaccumulation in gas1 mutant and for cell integrity; (b) homologous genes do not replace their function; (c) the regulation of CHS4-7 genes does not occur at transcriptional level. Control of the position of chitin synthesis could be important in protecting the bud from lysis.
English
Cell wall; Chitin; Stress
Settore BIO/11 - Biologia Molecolare
Articolo
Sì, ma tipo non specificato
30-set-2002
John Wiley & Sons
19
13
1113
1124
Periodico con rilevanza internazionale
info:eu-repo/semantics/article
Maintenance of cell integrity in the gas1 mutant of Saccharomyces cerevisiae requires the Chs3p-targeting and activation pathway and involves an unusual Chs3p localization / C. Carotti, L. Ferrario, C. Roncero, M.-H. Valdivieso, A. Duran, L. Popolo. - In: YEAST. - ISSN 0749-503X. - 19:13(2002 Sep 30), pp. 1113-1124.
none
Prodotti della ricerca::01 - Articolo su periodico
6
262
Article (author)
si
C. Carotti, L. Ferrario, C. Roncero, M.-H. Valdivieso, A. Duran, L. Popolo
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/2434/29101
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