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

Abstract

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.

References

[1] Nakamura H, Morita T, Sato C. Structural organizations of replicon domains during DNA synthetic phase in the mammalian nucleus. Exp Cell Res. 1986;165(2):291-7.
[2] Natsume T, Tanaka TU. Spatial regulation and organization of DNA replication within the nucleus. Chromosome Res. 2010;18(1):7-17.
[3] Hozák P, Hassan AB, Jackson DA, Cook PR. Visualization of replication factories attached to nucleoskeleton. Cell. 1993;73(2):361-73.
[4] Hozák P, Jackson DA, Cook PR. Replication factories and nuclear bodies: the ultrastructural characterization of replication sites during the cell cycle. J Cell Sci. 1994;107 ( Pt 8):2191-202.
[5] Philimonenko AA, Hodný Z, Jackson DA, Hozák P. The microarchitecture of DNA replication domains. Histochem Cell Biol. 2006;125(1-2):103-17.
[6] Jaunin F, Fakan S. DNA replication and nuclear architecture. J Cell Biochem. 2002;85(1):1-9.
[7] Liu DF, el-Alfy M, Leblond CP. DNA changes involved in the formation of metaphase chromosomes, as observed in mouse duodenal crypt cells stained by osmium-ammine. II. Tracing nascent DNA by bromodeoxyuridine into structures arising during the S phase. Anat Rec. 1995;242(4):449-61.
[8] Jaunin F, Visser AE, Cmarko D, Aten JA, Fakan S. A new immunocytochemical technique for ultrastructural analysis of DNA replication in proliferating cells after application of two halogenated deoxyuridines. J Histochem Cytochem. 1998;46(10):1203-9.
[9] Jaunin F, Visser AE, Cmarko D, Aten JA, Fakan S. Fine structural in situ analysis of nascent DNA movement following DNA replication. Exp Cell Res. 2000;260(2):313-23.
[10] Johnson RT, Rao PN. Mammalian cell fusion: induction of premature chromosome condensation in interphase nuclei. Nature. 1970;226(5247):717-22.
[11] Hanks SK, Rao PN. Initiation of DNA synthesis in the prematurely condensed chromosomes of G1 cells. J Cell Biol. 1980;87(1):285-91.
[12] Hanks SK, Gollin SM, Rao PN, Wray W, Hittelman WN. Cell cycle-specific changes in the ultrastructural organization of prematurely condensed chromosomes. Chromosoma. 1983;88(5):333-42.
[13] Hameister H, Sperling K. Description of a chromosome replication unit in individual prematurely condensed human S-phase chromosomes. Chromosoma. 1984;90(5):389-93.
[14] Danscher G. Localization of gold in biological tissue. A photochemical method for light and electronmicroscopy. Histochemistry. 1981;71(1):81-8.
[15] Gotoh E. Visualizing the dynamics of chromosome structure formation coupled with DNA replication. Chromosoma. 2007;116(5):453-62.
[16] Zatsepina OV, Polyakov VY, Chentsov YS. Chromonema and chromomere. Chromosoma. 1983;88(2):91–7.
[17] Zhironkina OA, Kurchashova SY, Brattseva AL, Cherepaninets VD, Strelkova OS, Belmont AS, Kireev II. Overcoming steric hindrances during replication of peripheral heterochromatin. Cell Tissue Biol. 2015;9(2):110–8