The first change, I171 to V177, was located far from the entrance to the heme access channel, while the other three changes are located close to or at the heme access channel and modify the accessibility to the cofactor.
Thus, we are not at liberty to modify the accessibility relation, should we wish to do so, unless we simultaneously revise the truth conditions associated with the DRS language.
For example, gene expression can be regulated at multiple levels that include epigenetic modulation by DNA methylation or through histone modifications that modify chromatin accessibility.
Also the local environment of these aromatic aa is important, since the presence of residues such as histidines (His) in their vicinity could modify their accessibility with respect to pH.
Theses complexes modify the accessibility of DNA regulatory sites through both repositioning (sliding) and ejecting nucleosomes.
This effect is independent of Th17 differentiation and is explained by the capacity of PP2Ac to modify chromatin accessibility at the Il17 locus by inducing defined epigenetic modifications.
In addition to the above-described processes, also histone modifications (methylation and acetylation) occur, which modify DNA accessibility to transcription factors (Fig. 1).
Such binding would be highly context-dependent; in particular it may depend on transcription factor abundance, and on epigenetic influences that modify DNA accessibility.
These changes may not affect CpGs that directly regulate the gene expression, but they may modify the accessibility of the promoter region to transcriptional regulation or affect genome stability.
NUP153 is known to affect the sub cellular distribution of transcription factor such as SMAD2, STAT1, and PU.1 [ 35], hence, altered NUP153 expression may modify the accessibility of key regulatory proteins.
