Chromatin remodelling proteins are essential for different aspects of metazoan biology, yet functional details of why these proteins are important are lacking. Although it is possible to describe the biochemistry of how they remodel chromatin, their chromatinbinding profiles in cell lines, and gene expression changes upon loss of a given protein, in very few cases can this easily translate into...

The blastulae of unincubated eggs of the quail, Coturnix coturnix japonica, have been bisected in ovo, using the technique of Lutz (1949). Some embryos were harvested after 24 h and found to possess two primitive streaks. Most were fixed at 48 h or 72 h. Some were found to have regulated to form almost normal single axes, whilst others had developed into duplicitas anterior embryos, separate tw...

With readily available transcriptome-wide data, understanding the role of each expressed gene is an essential next step. Although RNAi technologies allow for genome-wide screens in cell culture, these approaches cannot replace strategies for discovery in the embryo. Here we present, for the first time, a knockdown screen in mouse preimplantation embryos. Early mammalian development encompasses ...

T H E site of the future dorsal lip of the gastrula is already determined to a considerable degree at the grey-crescent region by the 8-cell stage, probably by means of interactions within the cortex (Curtis, 19626). But this determination is still easily disturbed because excision of the grey-crescent cortex from the 8-cell stage does not prevent the appearance of a dorsal lip. The embryo form...

The long-term developmental and behavioral consequences of mammalian embryo culture are unknown. By altering the culture medium with the addition of FCS, we wanted to determine whether mouse embryos cultured under suboptimal conditions develop aberrant mRNA expression of imprinting genes at the blastocyst stage and whether fetal development, growth, and behavior of adult mice are affected. One-...

Epigenetic alterations are increasingly recognized as causes of human cancers and disease. These aberrations are likely to arise during genomic reprogramming in mammalian preimplantation embryos, when their epigenomes are most vulnerable. However, this process is only partially understood because of the experimental inaccessibility of early-stage embryos. Here, we introduce a methodologic advan...

DNA methylation and demethylation are crucial for modulating gene expression and regulating cell differentiation. Functions and mechanisms of DNA methylation/demethylation in mammalian embryos are still far from being understood clearly. In this review we firstly describe new insights into DNA demethylation mechanisms, and secondly introduce the differences in active DNA methylation patterns in...

The blastulae of unincubated eggs of the quail, Coturnix coturnix japonica, have been bisected in ovo, using the technique of Lutz (1949). Some embryos were harvested after 24 h and found to possess two primitive streaks. Most were fixed at 48 h or 72 h. Some were found to have regulated to form almost normal single axes, whilst others had developed into duplicitas anterior embryos, separate tw...

The frequency distributions of polyadenylylated RNAs from the polysomes of sea urchin blastulae and gastrulae were estimated from their kinetics of hybridization with complementary DNA. Developmental decreases in complexity were observed among abundant, intermediate, and rare frequency classes. The class of highest abundance in the blastula polysomes had a complexity of 5.6 X 10(4) nucleotides ...

We know a great deal about the development of the mammalian embryo until the time that the blastocyst implants into the uterus. With model organisms such as the mouse, we have also developed a considerable understanding of development immediately around gastrulation as embryos can be recovered at this stage for short-term in vitro culture. However, the intervening period of development remained...