Talk:Oocyte Development
Loss of maternal ATRX results in centromere instability and aneuploidy in the mammalian oocyte and pre-implantation embryo
PLoS Genet. 2010 Sep 23;6(9). pii: e1001137.
Baumann C, Viveiros MM, De La Fuente R.
Female Germ Cell Biology Group, Department of Clinical Studies, University of Pennsylvania, Kennett Square, Pennsylvania, United States of America. Abstract
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.
PMID: 20885787
http://www.ncbi.nlm.nih.gov/pubmed/20885787
How eggs arrest at metaphase II: MPF stabilisation plus APC/C inhibition equals Cytostatic Factor http://www.celldiv.com/content/2/1/4
Balbiani body
- (Henneguy, 1887) is a cytoplasmic structure present in young immature oocytes in mammals and many other species
- transient structure composed of a large number of mitochondria, Golgi complexes, endoplasmic reticulum.
- ill-defined electron-dense granulofibrillar material that congregates at a perinuclear location
- as the oocyte matures it moves to a peripheral location in the oocyte cortex (in some species corresponding to the future vegetal pole) and disperses (reviewed by Kloc et al., 2004).
Function
- in some species contribute to the assembly and transportation of the germ plasm determinants to the cortex of the mature oocyte
- In mammals ( “inductive”, “regulative” or “epigenetic” mode of germ cell formation) do not have germ plasm determinants, the function remains largely obscure may include
- the controlled amplification of mitochondria or the creation of an asymmetry or polarity in the oocyte.
Reference: http://www.hh.um.es/pdf/Vol_25/25_2/de-Sousa-Lopes-25-267-276-2010.pdf
Henneguy F. (1887). Note sur la vesicle de Balbiani. C. R. Hebd. Seances Soc. Biol. Ses. Fil. 39, 69.
Kloc M., Bilinski S. and Etkin L.D. (2004). The Balbiani body and germ cell determinants: 150 years later. Curr. Top. Dev. Biol. 59, 1-36.
References
Egg coat proteins activate calcium entry into mouse sperm via CATSPER channels
Xia J, Ren D. Biol Reprod. 2009 Jun;80(6):1092-8. Epub 2009 Feb 11. PMID: 19211808
ZP2 and ZP3 traffic independently within oocytes prior to assembly into the extracellular zona pellucida
Hoodbhoy T, Avilés M, Baibakov B, Epifano O, Jiménez-Movilla M, Gauthier L, Dean J. Mol Cell Biol. 2006 Nov;26(21):7991-8. PMID: 17047254
