ISSN:
1573-4919
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
,
Chemistry and Pharmacology
,
Medicine
Notes:
Summary Many previously held concepts about the replication of chromatin have recently been revised, or seriously challenged. For instance, within the last two years, evidence has accumulated to indicate that newly synthesized DNA is not the sole site of deposition of newly synthesized histones, and that histories are not only made, but are assembled into chromatin in the absence of DNA synthesis. Furthermore, segregation of parental histories to daughter DNA duplexes may be bidirectional, rather than the previously accepted unidirectional mechanism. The storage of histories prior to assembly apparently involves historic pairs rather than octamers, and similarly, histories associate with DNA in (apparent) pairs, rather than as pre-assembled octameric units. It is currently questioned whether or not nucleoplasmin is involved in either historic storage or nucleosome assembly. The onset of histone synthesis has recently been found to occur in late G1 rather than in S, and thus is independent of DNA synthesis; however, the cessation of historic synthesis is linked to that of DNA. Thus, there emerges from this newly accumulated data the conclusion that chromatin biosynthesis is not as straightforward as was believed just a few years ago. As we review the evidence on each of these subjects, we attempt to point out directions for future experimentation.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00673705
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