Table 2.

Molecular memigenetic mechanisms

Known
DNA sequence: sequence elements are required for the binding of centromeric proteins in budding yeast. Also, the binding of TFs is dependent on DNA sequence [16, 26, 30]
Maintenance DNA methyltransferase activity: during S-phase, a fully methylated CpG dyad replicates to two hemi-methylated CpG dyads. Maintenance DNMT activity then converts hemi-methylated dyads to fully methylated dyads [34]
Diffusible TFs: if TFs are evicted from DNA at replication, or from condensed mitotic chomosomes, they can freely diffuse into daughter cells and reassemble into chromatin after chromosome decondensation [23, 24, 26, 31]
Bookmark or pioneer TFs: some TFs can remain bound to chromatin through mitosis, and thereby carry the memory of transcription into daughter cells [35–37]
Histone variant CENPA/CenH3: once incorporated and functional in specifying a centromere, it can self-propagate its incorporation at a genomic location, and hence centromere specification, through DNA replication [46, 47]
Possible
Histone variants and histone PTMs: the distribution of histone variants and their PTMs can be correlated with transcriptional activity. These correlations could be secondary to other mechanisms that carry transcriptional and structural memory of chromatin across cell division [15, 16, 48–51]