Summary: Previous results [E. Cabib, A. Sburlati, B. Bowers & S. J. Silverman (1989) Journal of Cell Biology 108, 1665-1672] strongly suggested that the lysis observed in daughter cells of Saccharomyces cerevisiae defective in chitin synthase 1 (Chs1) was caused by a chitinase that partially degrades the chitin septum in the process of cell separation. Consequently, it was proposed that in wild-type cells, Chs1 acts as a repair enzyme by replenishing chitin during cytokinesis. The chitinase requirement for lysis has been confirmed in two different ways: (a) demethylallosamidin, a more powerful chitinase inhibitor than the previously used allosamidin, is also a much better protector against lysis and (b) disruption of the chitinase gene in chs1 cells eliminates lysis. Reintroduction of a normal chitinase gene, by transformation of those cells with a suitable plasmid, restores lysis. The percentage of lysed cells in strains lacking Chs1 was not increased by elevating the chitinase level with high-copy-number plasmids carrying the hydrolase gene. Furthermore, the degree of lysis varied in different chs1 strains; lysis was abolished in chs1 mutants containing the scs1 suppressor. These results indicate that, in addition to chitinase, lysis requires other gene products that may become limiting.
BulawaC. E.,
SlaterM.,
CabibE.,
Au-YoungJ.,
SburlatiA.,
AdairW. L.JR,
RobbinsP. W.1986; The S. cerevisiae structural gene for chitin synthase is not required for chitin synthesis in vivo
. Cell 46:213–225
BulawaC. E.,
OsmondB. C.1990; Chitin synthase I and chitin synthase II are not required for chitin synthesis in vivo in Saccharomyces cerevisiae
. Proceedings of the National Academy of Sciences of the United States of America877424–7428
FernandezM. P.,
CorreaJ. U.,
CabibE.1982; Activation of chitin synthetase in permeabilized cells of a Saccharomyces cerevisiae mutant lacking proteinase B. Journal of Bacteriology 152:1255–1264
KangM S,
ElangoN.,
MattiaE.,
Au-YoungJ.,
RobbinsP. W.,
CabibE.1984; Isolation of chitin synthetase from Saccharomyces cerevisiae. Purification of an enzyme by entrapment in the reaction product. Journal of Biological Chemistry 259:14966–14972
KurandaM. J.,
RobbinsP. W.1987; Cloning and heterologous expression of glycosidase genes from Saccharomyces cerevisiae
. Proceedings of the National Academy of Sciences of the United States of America842585–2589
KurandaM. J.,
RobbinsP. W.1991; Chitinase is required for cell separation during growth of Saccharomyces cerevisiae
. Journal of Biological Chemistry 266:19758–19767
SakudaS.,
NishimotoY.,
OhiM.,
WatanabeM.,
TakayamaS.,
IsogaiA.,
YamadaY.1990; Effect of demethylallosamidin, a potent yeast chitinase inhibitor, on the cell division of yeast. Agricultural and Biological Chemistry 54:1333–1335
SburlatiA.,
CabibE.1986; Chitin synthethase 2, a presumptive participant in septum formation in Saccharomyces cerevisiae
. Journal of Biological Chemistry 261:15147–15152
ShawJ. A.,
MolP. C.,
BowersB.,
SilvermanS. J.,
ValdiviesoΜ. H.,
DuranA.,
CabibE.1991; The function of chitin synthases 2 and 3 in the Saccharomyces cerevisiae cell cycle
. Journal of Cell Biology 114:111–123
SilvermanS. J.,
SburlatiA.,
SlaterM. L.,
CabibE.1988; Chitin synthase 2 is essential for septum formation and cell division in Saccharomyces cerevisiae
. Proceedings of the National Academy of Sciences of the United States of America854735–4739
SilvermanS. J.,
ShawJ. A.,
CabibE.1991; Proteinase B is, indeed not required for chitin synthetase 1 function in Saccharomyces cerevisiae
. Biochemical and Biophysical Research Communciations 174:204–210