Abstract
The complete DNA replication sequence of the entire complement of chromosomes in the Chinese hamster may be studied by using the method of continuous H3-thymidine labeling and the method of 5-fluorodeoxyuridine block with H3-thymidine pulse labeling as relief. Many chromosomes start DNA synthesis simultaneously at multiple sites, but the sex chromosomes (the Y and the long arm of the X) begin DNA replication approximately 4.5 hours later and are the last members of the complement to finish replication. Generally, chromosomes or segments of chromosomes that begin replication early complete it early, and those which begin late, complete it late. Many chromosomes bear characteristically late replicating regions. During the last hour of the S phase, the entire Y, the long arm of the X, and chromosomes 10 and 11 are heavily labeled. The short arm of chromosome 1, long arm of chromosome 2, distal portion of chromosome 6, and short arms of chromosomes 7, 8, and 9 are moderately labeled. The long arm of chromosome 1 and the short arm of chromosome 2 also have late replicating zones or bands. The centromeres of chromosomes 4 and 5, and occasionally a band on the short arm of the X are lightly labeled.
Full Text
The Full Text of this article is available as a PDF (730.6 KB).
Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- CAIRNS J. The bacterial chromosome and its manner of replication as seen by autoradiography. J Mol Biol. 1963 Mar;6:208–213. doi: 10.1016/s0022-2836(63)80070-4. [DOI] [PubMed] [Google Scholar]
- HSU T. C., DEWEY W. C., HUMPHREY R. M. Radiosensitivity of cells of Chinese hamster in vitro in relation to the cell cycle. Exp Cell Res. 1962 Sep;27:441–452. doi: 10.1016/0014-4827(62)90010-1. [DOI] [PubMed] [Google Scholar]
- TAYLOR J. H. Asynchronous duplication of chromosomes in cultured cells of Chinese hamster. J Biophys Biochem Cytol. 1960 Jun;7:455–464. doi: 10.1083/jcb.7.3.455. [DOI] [PMC free article] [PubMed] [Google Scholar]
- TERASIMA T., TOLMACH L. J. X-ray sensitivity and DNA synthesis in synchronous populations of HeLa cells. Science. 1963 May 3;140(3566):490–492. doi: 10.1126/science.140.3566.490. [DOI] [PubMed] [Google Scholar]
- TILL J. E., WHITMORE G. F., GULYAS S. Deoxyribonucleic acid synthesis in individual L-strain mouse cells. II. Effects of thymidine starvation. Biochim Biophys Acta. 1963 Jun 25;72:277–289. [PubMed] [Google Scholar]