A CDC45 homolog in Arabidopsis is essential for meiosis, as shown by RNA interference-induced gene silencing.
CDC45 is required for the initiation of DNA replication in yeast and cell proliferation in mammals and functions as a DNA polymerase alpha loading factor in Xenopus. We have cloned a CDC45 homolog from Arabidopsis whose expression is upregulated at the G1/S transition and in young meiotic flower buds. One-third of Arabidopsis 35S:CDC45 T1 RNA interference lines are partially to completely sterile, and the proportion of sterile plants is increased by using a dmc1 promoter. T1 plants have decreased levels of the CDC45 transcript and contain 21- to 23-bp RNA fragments specific to the CDC45 gene. T2 transgenic lines, in which small RNA fragments are still present, were used to analyze S-phase entry by 5-bromodeoxyuridine incorporation, which was not altered compared with that in the wild type. However, microarray data show that other cell cycle genes are upregulated or downregulated. T2 plants also have highly reduced fertility. The severity of the phenotype is correlated with the levels of the CDC45 transcript and small RNA fragments. Severe chromosome fragmentation arising during meiosis, which is not the result of a defect in the repair of SPO11-induced double strand breaks, leads to abnormal chromosome segregation and defective pollen and ovule development.
Stevens
Rebecca
R
Institut de Biotechnologie des Plantes, Centre National de la Recherche Scientifique, Unité Mixte de Recherche 8618, Université de Paris-Sud, 91405 Orsay, France. rebecca.stevens@avignon.inra.fr
Grelon
Mathilde
M
Vezon
Daniel
D
Oh
Jaesung
J
Meyer
Peter
P
Perennes
Claudette
C
Domenichini
Severine
S
Bergounioux
Catherine
C
D017360:Arabidopsis / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism; D029681:Arabidopsis Proteins / Q000235:genetics* / Q000378:metabolism; D002453:Cell Cycle / Q000235:genetics* / Q000502:physiology; D018797:Cell Cycle Proteins / Q000235:genetics* / Q000378:metabolism; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000737:chemistry / Q000235:genetics; D005298:Fertility / Q000235:genetics / Q000502:physiology; D035264:Flowers / Q000254:growth & development; D018507:Gene Expression Regulation, Developmental; D018506:Gene Expression Regulation, Plant; D005816:Genetic Complementation Test; D008540:Meiosis / Q000235:genetics / Q000502:physiology; D008938:Mitosis / Q000235:genetics / Q000502:physiology; D009154:Mutation; D010641:Phenotype; D011058:Pollen / Q000254:growth & development; D034622:RNA Interference / Q000502:physiology*; D034741:RNA, Small Interfering / Q000235:genetics* / Q000378:metabolism; D034743:RNA-Induced Silencing Complex / Q000235:genetics* / Q000378:metabolism; D017422:Sequence Analysis, DNA; D000099257:Meiotic Recombination Protein SPO11
D029681:Arabidopsis Proteins; D018797:Cell Cycle Proteins; D018076:DNA, Complementary; D034741:RNA, Small Interfering; D034743:RNA-Induced Silencing Complex; C484059:CDC45 protein, Arabidopsis; C477460:Spo11-1 protein, Arabidopsis; D000099257:Meiotic Recombination Protein SPO11