New Function of Linker Histones

Scientists have long known that histones serve to package DNA and to provide a protein scaffolding around which the DNA organizes itself. Such organization allows gene regulation because certain segments of DNA may have access to each other in different configurations. Linker histones are known to bind to the DNA on the outside of the helix, blocking certain stretches of DNA, and thereby blocking access to certain genes. In recent studies, scientists report that linker histones may also sit inside the helix and may function in gene activation.

In a series of different experiment and models, researchers deduced that some linker histones contact histones that sit inside the DNA coils and the inside of the DNA itself. Further experiments demonstrated that the removal of the genes coding for a linker histone resulted in not only a constant expression of one gene, as expected, but also a drastically decreased expression of another gene. Although all may not function this way, certainly some linker histones may function to block the expression of certain genes or activate the expression of other genes.

"Linker Histones, DNA's Protein Custodians, Gain New Respect," by Elizabeth Pennisi, Science vol. 274, page 504, October 25, 1996

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