Biopolym. Cell. 1985; 1(5):227-233.
Reviews
Replicon organization of the genome of higher organisms: critical analysis of racts and hypothesis
1Liapunova N. A.
  1. Institute of Medical Genetics, Academy of Medical Sciences of the USSR
    Moscow, USSR

Abstract

The size measurement of replication units (replicons) by the method of DNA-fibre auto-radiography is critically analyzed. It is shown that the conception of «clusters of small replicons (30–50 u.m.)» is untenable. The model for organization of eucaryotic chromosome replication is suggested. This model is based on the known temporal order of replication of the functional chromosome blocks (G→G+→C) and on the existence of large replicons (100–200 u.m and more) being approximately equal to DNA fragments in one average-size functional block (300 u,m). The model is also based on the assumption Wiat the replicon initiations are grouped at three discrete short time intervals disrupted by prolonged time intervals during which only DNA chain elongation and replicon termination occur. The model explains uneven DNA synthesis during the S-period and facilitates a search of mechanisms for genetic control of the replication time sequence of different genome parts.

References

[1] Zakharov AF, Benyush VA, Kuleshov NP, Baranovska LI. Human Chromosomes: Atlas. M.: Medical, 1982. 261.
[2] Yunis JJ, Tsai MY. Mapping of polysomal messenger RNA and heterogeneous nuclear RNA to the lightly staining G-bands of human chromosomes. Cytogenet Cell Genet. 1978;22(1-6):364-7.
[3] Batuev AS, Orlov AA, Pirogov AA. Participation of primate frontal cortex in organizing short-term memory processes. Dokl Akad Nauk SSSR. 1979;247(4):997-1000.
[4] Ono T, Okada S. DNAase I digestion of early, middle, and late S phase replicating DNA in murine leukemia L5178Y cells. Biochim Biophys Acta. 1981;655(1):113-6.
[5] Goldman MA, Holmquist GP, Gray MC, Caston LA, Nag A. Replication timing of genes and middle repetitive sequences. Science. 1984;224(4650):686-92.
[6] Bak AL, Jorgensen AL, Zeuthen J. Chromosome banding and compaction. Hum Genet. 1981;57(2):199-202.
[7] Zakharov AF, Egolina NA. Correlation between pattern of DNA replication and chromosome banding. Biol Zbl. 1976; 95:327-334.
[8] Cairns J. Autoradiography of HeLa cell DNA. J Mol Biol. 1966;15(1):372-3.
[9] Huberman JA, Riggs AD. On the mechanism of DNA replication in mammalian chromosomes. J Mol Biol. 1968;32(2):327-41.
[10] Callan HG. Replication of DNA in the chromosomes of eukaryotes. Proc R Soc Lond B Biol Sci. 1972;181(62):19-41.
[11] Edenberg HJ, Huberman JA. Eukaryotic chromosome replication. Annu Rev Genet. 1975;9:245-84.
[12] Hand R. Eucaryotic DNA: organization of the genome for replication. Cell. 1978;15(2):317-25.
[13] Ananiev EV, Polukarova LG, Yurov YB. Replication of chromosomal DNA in diploid Drosophila melanogaster cells cultured in vitro. Chromosoma. 1977;59(3):259-72.
[14] Iurov IuB, Liapunova NA. Rate of DNA replication and size of replicons in human diploid cells. Mol Biol (Mosk). 1976;10(5):1085-93.
[15] Wilson BG. DNA replication in the amphibia. Chromosoma. 1975;51(3):213-24.
[16] Yurov YB. Do clusters of replication units in the mammalian cells exist? Exp Cell Res. 1979;123(2):369-74.
[17] Callan HG. DNA replication in the chromosomes of eukaryotes. In: Molecular Cytogenetics . Eds B. A. Hamkalo, J. Papaconstantinou. New York: Plenum publ. corp., 1973; p. 31-47.
[18] Yurov YB, Liapunova NA. The units of DNA replication in the mammalian chromosomes: evidence for a large size of replication units. Chromosoma. 1977;60(3):253-67.
[19] Housman D, Huberman JA. Changes in the rate of DNA replication fork movement during S phase in mammalian cells. J Mol Biol. 1975;94(2):173-81.
[20] Khaitova NM, Il'ina GS, Liapunova NA. Organization of mammalian genome replication: data on the high rate of DNA replication in replicons of structural heterochromatin. Tsitologiia. 1980;22(6):640-5.
[21] Kapp LN, Painter RB. Multiple thymidine incorporation peaks in the S phase of synchronous human diploid fibroblasts. Exp Cell Res. 1977;107(2):428-31.
[22] Kapp LN, Painter RB. X-ray inhibition of DNA synthesis at discrete times during S phase in synchronous human diploid fibroblasts. Radiat Res. 1982;89(2):424-7.
[23] Lyapunov NA, Lavrushina OM, Dulatova ShN. Using bleomycin to demonstrate clustering acts in DNA replication initiation in the S-phase of the mitotic cycle in cultured human cells. In the book.: VIII Proc. symposium. "Structure and function of the cell nucleus": Proc. of reports. Pushchino, 1984, p. 269-270.
[24] Wille JJ Jr, Kauffman SA. Premature replication of late S period DNA regions in early S nuclei transferred to late S cytoplasm by fusion in Physarum polycephalum. Biochim Biophys Acta. 1975;407(2):158-73.
[25] Epifanova OI. Study the regulatory mechanisms of the mitotic cycle with inhibitors of translation and transcription. In book.: Cell Cycle. Nauka, Moscow, 1973, p. 72-103.