The (1,3)beta-D-glucan synthase subunit Bgs1p is responsible for the fission yeast primary septum formation.
Cytokinesis is a crucial event in the cell cycle of all living cells. In fungal cells, it requires co-ordinated contraction of an actomyosin ring and synthesis of both plasmatic membrane and a septum structure that will constitute the new cell wall end. Schizosaccharomyces pombe contains four essential putative (1,3)beta-d-glucan synthase catalytic subunits, Bgs1p to Bgs4p. Here we examined the function of Bgs1p in septation by studying the lethal phenotypes of bgs1(+) shut-off and bgs1Delta cells and demonstrated that Bgs1p is responsible and essential for linear (1,3)beta-d-glucan and primary septum formation. bgs1(+) shut-off generates a more than 300-fold Bgs1p reduction, but the septa still present large amounts of disorganized linear (1,3)beta-d-glucan and partial primary septa. Conversely, both structures are absent in bgs1Delta cells, where there is no Bgs1p. The septum analysis of bgs1(+)-repressed cells indicates that linear (1,3)beta-d-glucan is necessary but not sufficient for primary septum formation. Linear (1,3)beta-d-glucan is the polysaccharide that specifically interacts with the fluorochrome Calcofluor white in fission yeast. We also show that in the absence of Bgs1p abnormal septa are formed, but the cells cannot separate and eventually die.
Cortés
Juan Carlos G
JC
Instituto de Microbiología Bioquímica, Consejo Superior de Investigaciones Científicas (CSIC)/Universidad de Salamanca, 37007 Salamanca, Spain.
Konomi
Mami
M
Martins
Ivone M
IM
Muñoz
Javier
J
Moreno
M Belén
MB
Osumi
Masako
M
Durán
Angel
A
Ribas
Juan Carlos
JC
D001557:Benzenesulfonates / Q000378:metabolism; D020134:Catalytic Domain; D002473:Cell Wall / Q000737:chemistry / Q000378:metabolism*; D048749:Cytokinesis; D015966:Gene Expression Regulation, Fungal; D005964:Glucosyltransferases / Q000235:genetics / Q000378:metabolism*; D016253:Microscopy, Immunoelectron; D012568:Schizosaccharomyces / Q000166:cytology / Q000201:enzymology*; D029702:Schizosaccharomyces pombe Proteins / Q000235:genetics / Q000378:metabolism; D047071:beta-Glucans / Q000378:metabolism
D001557:Benzenesulfonates; D029702:Schizosaccharomyces pombe Proteins; D047071:beta-Glucans; C007061:C.I. Fluorescent Brightening Agent 28; D005964:Glucosyltransferases; C020570:1,3-beta-glucan synthase