Nucleosome Cores Assembled in Vitro Occupy Two Preferred Frames Flanking the Histone H1 Gene from Psammechinus miliaris

The histone h22 gene quintet of Psammechinus miliaris contains two simple sequence motifs. One sequence, [d(C-T)]23, is located in the H2A-H1 spacer area, and another, [d(G-A)]16, is located in the H1-H4 spacer area. Fragments containing these sequences were inserted into pGV403 plasmids to allow strand-specific end labeling. Nucleosome cores assembled “in vitro” in the presence of poly(glutamic acid) on these labeled linear fragments occupy in each of the fragments a preferred frame which includes the repetitive sequence motif. The frames are characterized by an approximately 10 base pair DNase I digestion periodicity. On the remainder of the fragments, nucleosome cores are assembled, either in a random manner or in a number of complex frames that cannot be resolved. © 1987, American Chemical Society. All rights reserved.