Biopolym. Cell. 2015; 31(4):249-254.
Structure and Function of Biopolymers
Ultrastructural organization of replicating chromatin in prematurely condensed chromosomes
1Arifulin E. A.
  1. A. N. Belozersky Institute of Physico-Chemical Biology
    M. V. Lomonosov Moscow State University
    Leninskie gory, house 1, building 40, Moscow, Russian Federation, 119992


Aim. The ultrastructural aspect of replicating chromatin organization is a matter of dispute. Here, we have analyzed the ultrastructural organization of replication foci using prematurely condensed chromosomes (PCC). Methods. To investigate the ultrastructure of replicating chromatin, we have used correlative light and electron microscopy as well as immunogold staining. Results. Replication in PCC occurs in the gaps between condensed chromatin domains. Using correlative light and electron microscopy, we observed that the replication foci contain decondensed chromatin as well as 80 and 130 nm globules, those were also found in condensed non-replicating chromatin domains. Using immunogolding, we demonstrated that DNA replication in S-phase PCC occurs in loose chromatin on the periphery of dense chromatin domains. Conclusion. Replication in PCC occurred in the decondensed chromatin neighboring the condensed chromatin without formation of special structures.
Keywords: chromatin, replication, prematurely condensed chromosomes (PCC), ultrastructure.


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