Loss of maternal ATRX results in centromere instability and aneuploidy in the mammalian oocyte and pre-implantation embryo.
The α-thalassemia/mental retardation X-linked protein (ATRX) is a chromatin-remodeling factor known to regulate DNA methylation at repetitive sequences of the human genome. We have previously demonstrated that ATRX binds to pericentric heterochromatin domains in mouse oocytes at the metaphase II stage where it is involved in mediating chromosome alignment at the meiotic spindle. However, the role of ATRX in the functional differentiation of chromatin structure during meiosis is not known. To test ATRX function in the germ line, we developed an oocyte-specific transgenic RNAi knockdown mouse model. Our results demonstrate that ATRX is required for heterochromatin formation and maintenance of chromosome stability during meiosis. During prophase I arrest, ATRX is necessary to recruit the transcriptional regulator DAXX (death domain associated protein) to pericentric heterochromatin. At the metaphase II stage, transgenic ATRX-RNAi oocytes exhibit abnormal chromosome morphology associated with reduced phosphorylation of histone 3 at serine 10 as well as chromosome segregation defects leading to aneuploidy and severely reduced fertility. Notably, a large proportion of ATRX-depleted oocytes and 1-cell stage embryos exhibit chromosome fragments and centromeric DNA-containing micronuclei. Our results provide novel evidence indicating that ATRX is required for centromere stability and the epigenetic control of heterochromatin function during meiosis and the transition to the first mitosis.
Baumann
Claudia
C
Female Germ Cell Biology Group, Department of Clinical Studies, University of Pennsylvania, Kennett Square, Pennsylvania, United States of America.
Viveiros
Maria M
MM
De La Fuente
Rabindranath
R
D000782:Aneuploidy; D000818:Animals; D001755:Blastocyst / Q000166:cytology / Q000378:metabolism*; D002352:Carrier Proteins / Q000378:metabolism; D002503:Centromere / Q000378:metabolism*; D043171:Chromosomal Instability / Q000235:genetics*; D020090:Chromosome Segregation / Q000235:genetics; D033481:Chromosomes, Mammalian / Q000378:metabolism; D056970:Co-Repressor Proteins; D004265:DNA Helicases / Q000172:deficiency* / Q000235:genetics / Q000378:metabolism; D005260:Female; D005298:Fertility / Q000235:genetics; D055785:Gene Knockdown Techniques; D006570:Heterochromatin / Q000378:metabolism; D006657:Histones / Q000378:metabolism; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins / Q000378:metabolism; D051379:Mice; D008822:Mice, Transgenic; D008938:Mitosis / Q000235:genetics; D023421:Models, Animal; D018832:Molecular Chaperones; D009687:Nuclear Proteins / Q000172:deficiency* / Q000235:genetics / Q000378:metabolism; D009865:Oocytes / Q000166:cytology / Q000378:metabolism*; D009928:Organ Specificity / Q000235:genetics; D010766:Phosphorylation; D034622:RNA Interference; D000075924:X-linked Nuclear Protein
D002352:Carrier Proteins; D056970:Co-Repressor Proteins; C491473:Daxx protein, mouse; D006570:Heterochromatin; D006657:Histones; D047908:Intracellular Signaling Peptides and Proteins; D018832:Molecular Chaperones; D009687:Nuclear Proteins; D004265:DNA Helicases; C490462:Atrx protein, mouse; D000075924:X-linked Nuclear Protein