The meiotic protein SWI1 is required for axial element formation and recombination initiation in Arabidopsis.
We report the detailed characterization of SWITCH1 (SWI1) an Arabidopsis thaliana protein that has been linked with the establishment of sister chromatid cohesion during meiosis. Using a combination of cytological methods including immunolocalization of meiotic chromosome-associated proteins we show that SWI1 is required for formation of axial elements. Our studies reveal that the swi1-2 mutation prevents the formation of RAD51 foci during meiotic prophase and suppresses the chromosome fragmentation phenotype of the recombination-defective dif1-1 mutant. Together, these data suggest that SWI1 may be required for meiotic recombination initiation. Finally we raised an antibody against SWI1 and showed, by immunolocalization coupled with bromodeoxyuridine incorporation experiments, that SWI1 is expressed exclusively in meiotic G(1) and S phase. Thus, SWI1 appears to be required for early meiotic events that are at the crossroad of sister chromatid cohesion, recombination and axial element formation. The possible inter-relationship between these processes and the function of SWI1 are discussed.
Mercier
Raphael
R
School of Biosciences, The University of Birmingham, Birmingham, B15 2TT, UK. rmercier@versailles.inra.fr
Armstrong
Susan J
SJ
Horlow
Christine
C
Jackson
Neil P
NP
Makaroff
Christopher A
CA
Vezon
Daniel
D
Pelletier
Georges
G
Jones
Gareth H
GH
Franklin
F Christopher H
FC
D000483:Alleles; D017360:Arabidopsis / Q000235:genetics*; D029681:Arabidopsis Proteins; D018797:Cell Cycle Proteins; D002842:Chromatids; D002843:Chromatin / Q000378:metabolism; D002868:Chromosomal Proteins, Non-Histone; D002875:Chromosomes / Q000378:metabolism / Q000648:ultrastructure; D005656:Fungal Proteins; D016193:G1 Phase; D017343:Genes, Plant; D006579:Heterozygote; D007150:Immunohistochemistry; D008540:Meiosis; D008856:Microscopy, Fluorescence; D009154:Mutation; D009687:Nuclear Proteins / Q000378:metabolism; D010641:Phenotype; D018521:Plant Physiological Phenomena; D011995:Recombination, Genetic; D016196:S Phase; D014157:Transcription Factors / Q000235:genetics* / Q000502:physiology*; D000097722:Cohesins
D029681:Arabidopsis Proteins; D018797:Cell Cycle Proteins; D002843:Chromatin; D002868:Chromosomal Proteins, Non-Histone; D005656:Fungal Proteins; D009687:Nuclear Proteins; D014157:Transcription Factors; D000097722:Cohesins; C513099:SWI1 protein, Arabidopsis