Depletion of Drad21/Scc1 in Drosophila cells leads to instability of the cohesin complex and disruption of mitotic progression.
BACKGROUND
The coordination of cell cycle events is necessary to ensure the proper duplication and dissemination of the genome. In this study, we examine the consequences of depleting Drad21 and SA, two non-SMC subunits of the cohesin complex, by dsRNA-mediated interference in Drosophila cultured cells.


RESULTS
We have shown that a bona fide cohesin complex exists in Drosophila embryos. Strikingly, the Drad21/Scc1 and SA/Scc3 non-SMC subunits associate more intimately with one another than they do with the SMCs. We have observed defects in mitotic progression in cells from which Drad21 has been depleted: cells delay in prometaphase with normally condensed, but prematurely separated, sister chromatids and with abnormal spindle morphology. Much milder defects are observed when SA is depleted from cells. The dynamics of the chromosome passenger protein, INCENP, are affected after Drad21 depletion. We have also made the surprising observation that SA is unstable in the absence of Drad21; however, we have shown that the converse is not true. Interference with Drad21 in living Drosophila embryos also has deleterious effects on mitotic progression.


CONCLUSIONS
We conclude that Drad21, as a member of a cohesin complex, is required in Drosophila cultured cells and embryos for proper mitotic progression. The protein is required in cultured cells for chromosome cohesion, spindle morphology, dynamics of a chromosome passenger protein, and stability of the cohesin complex, but apparently not for normal chromosome condensation. The observation of SA instability in the absence of Drad21 implies that the expression of cohesin subunits and assembly of the cohesin complex will be tightly regulated.
Vass
Sharron
S
Wellcome Trust Centre for Cell Biology, Institute of Cell and Molecular Biology, University of Edinburgh, Michael Swann Building, King's Buildings, Mayfield Road, Edinburgh EH9 3JR, Scotland, United Kingdom.
Cotterill
Sue
S
Valdeolmillos
Ana M
AM
Barbero
José L
JL
Lin
Enmoore
E
Warren
William D
WD
Heck
Margarete M S
MM
D000818:Animals; D018797:Cell Cycle Proteins / Q000235:genetics / Q000378:metabolism*; D048429:Cell Size; D002478:Cells, Cultured; D002868:Chromosomal Proteins, Non-Histone / Q000378:metabolism; D002875:Chromosomes / Q000378:metabolism; D019926:Cyclin B / Q000378:metabolism; D029721:Drosophila Proteins / Q000235:genetics / Q000378:metabolism*; D004331:Drosophila melanogaster / Q000033:anatomy & histology / Q000196:embryology / Q000502:physiology*; D005656:Fungal Proteins; D046911:Macromolecular Substances; D008938:Mitosis / Q000502:physiology*; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism*; D021122:Protein Subunits / Q000235:genetics / Q000378:metabolism*; D034622:RNA Interference; D012330:RNA, Double-Stranded / Q000235:genetics / Q000378:metabolism; D008941:Spindle Apparatus / Q000378:metabolism; D000097722:Cohesins
D018797:Cell Cycle Proteins; D002868:Chromosomal Proteins, Non-Histone; D019926:Cyclin B; D029721:Drosophila Proteins; D005656:Fungal Proteins; D046911:Macromolecular Substances; D009687:Nuclear Proteins; D021122:Protein Subunits; D012330:RNA, Double-Stranded; D000097722:Cohesins; C503698:CycB protein, Drosophila; C410884:vtd protein, Drosophila