The alpha-glucanase Agn1p is required for cell separation in Schizosaccharomyces pombe.
BACKGROUND
In animal cells, cytokinesis occurs by constriction of an actomyosin ring. In fission yeast, ring constriction is followed by deposition of a multilayered division septum that must be cleaved to release the two daughter cells. Although many studies have focused on the actomyosin ring and septum assembly, little is known about the later steps involving the cleavage of the cell wall.


RESULTS
We identified a novel gene in Schizosaccharomyces pombe, namely the agn1(+) gene that has homology to fungal 1,3-alpha-glucanases (mutanases). Disruption of the agn1(+) gene is not lethal to the cells, but does interfere with their separation, whereas overexpression of Agn1p is toxic and causes cell lysis. Agn1p levels reach a peak during septation and the protein localizes to the septum region before cell separation. Moreover, agn1(+) is responsible for the 1,3-alpha-glucanase activity, which shows a maximum at the end of septation.


CONCLUSIONS
Our results clearly suggest the existence of a relationship between agn1(+), 1,3-alpha-glucanase activity and the completion of septation in S. pombe. Agn1p could be involved in the cleavage of the cylinder of the old wall that surrounds the primary septum, a region rich in alpha-glucans.
García
Ignacio
I
Instituto de Microbiología Bioquímica, CSIC/Universidad de Salamanca and Departamento de Microbiología y Genética, Universidad de Salamanca, Edificio Departamental, 37007 Salamanca, Spain.
Jiménez
David
D
Martín
Victoria
V
Durán
Angel
A
Sánchez
Yolanda
Y
D002455:Cell Division / Q000235:genetics*; D048749:Cytokinesis; D006026:Glycoside Hydrolases / Q000378:metabolism*; D008857:Microscopy, Interference; D009154:Mutation; D010641:Phenotype; D029702:Schizosaccharomyces pombe Proteins / Q000235:genetics* / Q000502:physiology
D029702:Schizosaccharomyces pombe Proteins; D006026:Glycoside Hydrolases; C021780:exo-1,3-alpha-glucanase