Chitin Synthesis -Related Proteins in the Chitin -Less Yeast Schizosaccharomyces Pombe

I identified and characterized four chitin synthesis-related proteins in S. pombe. Two of these, SpChs1p and SpChs2p are homologs of S. cerevisiae chitin synthases and two, SpChs4p and SpChs5p, are homologs of S. cerevisiae proteins that regulate, respectively, the activity and localization of chitin synthase III. I demonstrated that SpChs1p and SpChs2p can catalyze the synthesis of chitin in an in vitro assay. Genetic disruption of Spchs1 + and Spchs2+ showed that neither is essential for viability, nor is the simultaneous disruption of both genes detrimental to normal cell morphogenesis. However loss of SpChs1p resulted in an increased tolerance to osmotic shock, and loss of SpChs2p resulted in an increased tolerance to heat-shock. Both the deletion or the overproduction of SpChs4p and SpChs5p led to phenotypes. Deletion of Spchs4 + resulted in cells with a cell separation defect, and these cells had also acquired an increased tolerance to osmotic stress. Overproduction of SpChs4p, on the other hand, resulted in large multinucleate and multiseptate cells. Loss of SpChs5p led to an increased sensitivity to KCl, whereas overproduction resulted in an increase tolerance to the salt. Taken together these results indicate that SpChs1p, SpChs2p, SpChs4p and SpChs5p may play a role in S. pombe morphogenesis. Although it is likely that both SpChs1p and SpChs2p catalyze the synthesis of chitin in viv0, chitin may only be a necessary structural cell wall component under certain conditions. The role of SpChs4p and SpChs5p in fission yeast chitin synthesis is less clear. It is possible that their functions are unconnected with chitin synthesis.

Name thesis:degree_name

Ph.D.

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Biochemistry

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2015

Author dc:creator

• Jensen, Irene Elisabeth

Contributors dc:contributor

• Peter A.B.Orlean

• Chemistry, Biochemistry

Language dc:language

eng

Identifier

(MiAaPQ)AAI9971105

OAI identifier oai:identifier

oai:www.ideals.illinois.edu:2142/84912