AtREC8 and AtSCC3 are essential to the monopolar orientation of the kinetochores during meiosis.
The success of the first meiotic division relies (among other factors) on the formation of bivalents between homologous chromosomes, the monopolar orientation of the sister kinetochores at metaphase I and the maintenance of centromeric cohesion until the onset of anaphase II. The meiotic cohesin subunit, Rec8 has been reported to be one of the key players in these processes, but its precise role in kinetochore orientation is still under debate. By contrast, much less is known about the other non-SMC cohesin subunit, Scc3. We report the identification and the characterisation of AtSCC3, the sole Arabidopsis homologue of Scc3. The detection of AtSCC3 in mitotic cells, the embryo lethality of a null allele Atscc3-2, and the mitotic defects of the weak allele Atscc3-1 suggest that AtSCC3 is required for mitosis. AtSCC3 was also detected in meiotic nuclei as early as interphase, and bound to the chromosome axis from early leptotene through to anaphase I. We show here that both AtREC8 and AtSCC3 are necessary not only to maintain centromere cohesion at anaphase I, but also for the monopolar orientation of the kinetochores during the first meiotic division. We also found that AtREC8 is involved in chromosome axis formation in an AtSPO11-1-independent manner. Finally, we provide evidence for a role of AtSPO11-1 in the stability of the cohesin complex.
Chelysheva
Liudmila
L
Institut Jean-Pierre Bourgin, Station de Génétique et d'Amélioration des Plantes, INRA de Versailles, Route de Saint-Cyr, 78026 Versailles CEDEX, France.
Diallo
Stéphanie
S
Vezon
Daniel
D
Gendrot
Ghislaine
G
Vrielynck
Nathalie
N
Belcram
Katia
K
Rocques
Nathalie
N
Márquez-Lema
Angustias
A
Bhatt
Anuj M
AM
Horlow
Christine
C
Mercier
Raphaël
R
Mézard
Christine
C
Grelon
Mathilde
M
D000705:Anaphase; D017360:Arabidopsis / Q000166:cytology* / Q000235:genetics / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D018797:Cell Cycle Proteins / Q000378:metabolism*; D016764:Cell Polarity; D002868:Chromosomal Proteins, Non-Histone; D032461:Chromosomes, Plant / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000378:metabolism; D005656:Fungal Proteins / Q000378:metabolism; D018745:Genome, Plant; D018386:Kinetochores / Q000378:metabolism*; D008540:Meiosis; D009154:Mutation / Q000235:genetics; D009687:Nuclear Proteins / Q000378:metabolism; D010641:Phenotype; D021381:Protein Transport; D051135:Rad51 Recombinase / Q000378:metabolism; D011995:Recombination, Genetic; D000097722:Cohesins
D029681:Arabidopsis Proteins; D018797:Cell Cycle Proteins; D002868:Chromosomal Proteins, Non-Histone; D004268:DNA-Binding Proteins; D005656:Fungal Proteins; D009687:Nuclear Proteins; D051135:Rad51 Recombinase; D000097722:Cohesins; C411742:ASY1 protein, Arabidopsis; C507256:REC8 protein, Arabidopsis; C507252:SCC3 protein, Arabidopsis; C495146:ATRAD51 protein, Arabidopsis