Chromatin Structure: Molecular Machines May Aid Gene Expression

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Science  08 Dec 1995:
Vol. 270, Issue 5242, pp. 1589-1590
DOI: 10.1126/science.270.5242.1589


In order to pack all of the DNA into the chromosomes, the cells of higher organisms wrap it around a core of proteins called histones, much as thread is wound around a spool. But that makes the DNA hard to get at, raising questions about how the enzymes and other materials needed to copy the DNA into RNA, which is the first step in gene expression, might gain access to the DNA. Recent evidence now suggests that this is accomplished with the aid of molecular machines, energy-consuming proteins in the cell's nucleus, that disrupt the histones, allowing the gene-transcribing machinery in to do its job.