Of these transcription factors, some activate and others repress TPE while others contribute to boundary activity, which limits the spread of silencing.
However, boundary activity is stage specific and pHS1×4 does not block the NE from activating LacZ expression in the CNS in older embryos (Aoki et al., 2008 ).
These findings indicate that BRD2 supports boundary activity, and they raise the possibility that pharmacologic BET inhibitors can influence gene expression in part by perturbing domain boundary function.
The deformation of nanocrystalline metals is a complex process that involves a cascade of plastic events, including dislocation motion, grain boundary activity and cavitation.
When the degree of deformation exceeds 1000%, the microstrain and the grain boundary energy tend to saturated values, implying that this deformation process is dominated by grain boundary activity rather than lattice dislocation.
We assume that a suitable initial condition is specified for (1), and we aim to impose on the corresponding solution (u(boldsymbol {x},t)) the Dirichlet boundary condition u(boldsymbol {x},t) vert_{boldsymbol {x} inpartialvarOmega} = u_{text{BC}}, (2) where (u_{text{BC}}) is the prescribed boundary activity.
Together, these findings suggest that the mechanisms underlying boundary activity in Evx2-HoxD are different from those underlying boundary activity in the β-globin and H19 systems [21], [22].
It is possible that loss of boundary activity and/or the redistribution of a limiting silencing factor such as Sir3p [36], [37], [37] could indirectly produce these effects.
Furthermore, we found that this boundary sequence functions in a tissue-specific manner, and that the regulation of tissue specificity can be separated from the boundary activity.
In accordance with these observations, lack of H3K9 dimethylation and DNA methylation of the PD1 transgene truncated at the barrier site is consistent with intermediate transcriptional silencing and suggest the existence of yet other elements that contribute to boundary activity.
The loss of boundary activity is specific to constituents of the Elba complex, as injection of dsRNA for the closely related insv did not disrupt boundary activity.
