A-type Lamins Intervene When Chromatin is Targeted

Regulation of gene activity is mainly concerned with nuclear organization.

The associations of the regulatory regions of the genome with the nuclear lamina have been identified.

Information about these lamina-associated domains (LADs) directed to the nuclear lamina is sparse.

Chromosomal insertion site system was used to identify small sequences from borders of fibroblast-specific variable LADs that are sufficient to target these ectopic sites to the nuclear periphery.

YY1 (Ying-Yang1) binding sites as enriched in relocating sequences were identified. There was no lamina association as lamina A was not knocked down like YY1 or lamin A/C.

In addition, targeted recruitment of YY1 proteins facilitated ectopic LAD formation dependent on histone H3 lysine 27 trimethylation and histone H3 lysine di- and trimethylation.

The results also reveal that endogenous loci appear to be dependent on lamin A/C, YY1, H3K27me3, and H3K9me2/3 for maintenance of lamina-proximal positioning.

Source: Medindia