The timing of the MBT has been suggested to depend on the titration of a maternally deposited repressive factor by increasing amounts of embryonic DNA (Newport and Kirschner, 1982a,b).
We used the maternal Gal4 shRNA system to build a gene expression atlas of an embryo depleted of bcd, a maternally deposited transcription factor crucial for anterior-posterior patterning of the Drosophila melanogaster embryo.
Early histone acetylation is strongly associated with regions that we have previously shown to be bound in early embryos by the maternally deposited transcription factor Zelda, suggesting that Zelda triggers a cascade of events, including the accumulation of specific histone modifications, that plays a role in the subsequent activation of these sequences.
We have previously shown that a single seven base-pair DNA motif is found in the vast majority of patterning enhancers active in the cellular blastoderm (Li et al., 2008), and that the maternally deposited transcription factor Zelda (ZLD) (Liang et al., 2008), which binds to this sequence, is present at these enhancers by mitotic cycle 8, in the early phase of the MZT (Harrison et al., 2011).
The correct positioning of the 2.1-Å R1 R7 structure into the 8-Å map of the complete particle (this work) as well as in the 3.5-Å averaged map, calculated from the deposited structure factors (PDB id; 2ZV4) of the Tanaka structure (Tanaka et al, 2009), reveals important charge complementarity at the interface between the two vault halves.
All sexually produced animals must pass control of the gene regulatory network from maternal factors deposited in the egg to newly synthesized gene products, synthesized after the embryo begins developing, of the zygotic genome.
Although we still postulate that proteins that remain associated with the mRNA after splicing influence NMD, we propose that the effect is not due to a specific factor deposited at a particular distance before the splice junction (Le Hir et al, 2000, 2001).
Moreover, gene models for putative maize NAC transcription factors, deposited at Grassius Grass Regulatory Information Server (http://www.grassius.org/index.html), were blasted against the assembled maize genome.
Thus, it is plausible that blood-borne signalling proteins, such as coagulation factors deposited at sites of physical damage, are detected by OPCs and act as surrogate markers of ongoing repair of the primary injury.
