Chromatin fiber polymorphism triggered by variations of DNA linker lengths

• DOI: 10.1073/pnas.1315872111
• Publication Date: 2014-05-21T01:53:54Z
• Authors: Rosana Collepardo...; Tamar Schlick
• Keywords: Linker; Interphase; Linker DNA

Deciphering the factors that control chromatin fiber structure is key to understanding fundamental chromosomal processes. Although details remain unknown, it becoming clear polymorphic depending on internal and external factors. In particular, different lengths of linker DNAs joining successive nucleosomes (measured in nucleosome-repeat or NRLs) characterize cell types cycle stages produce structures. NRL also nonuniform within single fibers, but how this diversity affects not clear. Here we perform Monte Carlo simulations a coarse-grained oligonucleosome model help interpret subject intrafiber variations, as relevant proliferating cells interphase chromatin, fibers remodeling factors, regulatory DNA sequences. We find variations have profound impact structure, with wide range architectures emerging (highly bent narrow forms, canonical irregular zigzag conformations), NRLs mixed. This stabilization forms might allow regulate both compaction selective exposure. The spanning sharply structures, like hairpins loops, arise from large are surprisingly more compact than uniform They distinguished by tail-mediated far-nucleosome interactions, addition near-nucleosome interactions 30-nm fibers. Polymorphism consistent chromatin's diverse biological functions heterogeneous constituents. Intrafiber may contribute bending looping thus distant communication associated