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The ‘SUN’ family: yeast SUN4 / SCW3 is involved in cell septation
Author(s) -
Mouassite Mariam,
Camougrand Nadine,
Schwob Etienne,
Demaison Geneviève,
Laclau Murielle,
Guérin Martine
Publication year - 2000
Publication title -
yeast
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.923
H-Index - 102
eISSN - 1097-0061
pISSN - 0749-503X
DOI - 10.1002/1097-0061(200007)16:10<905::aid-yea584>3.0.co;2-1
Subject(s) - biology , cell division , cell cycle , microbiology and biotechnology , nocodazole , cell , biogenesis , morphogenesis , genetics , mutant , phenotype , gene , cell type , cytokinesis , mitosis , cytoskeleton
SUN4 is the fourth member of the SUN gene family from S. cerevisiae , whose products display high homology in their 258 amino acid C‐terminal domain. S IM1 , U TH1 , N CA3 (the founding members) are involved in different cellular processes (DNA replication, ageing, mitochondrial biogenesis) and it is shown herein that SUN4 plays a role in the cell septation process. sun4Δ cells are larger than wild‐type and begin a new cell cycle before they have separated from their mother cell. This phenotype is more pronounced in sun4 Δ cells also deleted for UTH1 . FACS analysis shows apparent polyploidy which disappears when the cell cycle is arrested by mating factor or nocodazole, indicating that cell septation is delayed without modification of the doubling time. Elutriated sun4 Δ uth1 Δ daughter cells are born larger, and therefore enter S phase sooner than their wild‐type counterpart. S phase duration, as well as timing of Clb2 degradation, is normal, but cell septation is delayed. Sun4p/Scw3p was recently described as a cell wall protein (Cappellaro et al ., 1998) and, consistent with this notion, electron micrographs of sun4Δ cells show defects in the final steps of cell wall septation. Our data suggest that Sun4p and Uth1p might contribute to the regulated process of cell wall morphogenesis and septation. Copyright © 2000 John Wiley & Sons, Ltd.