Werner Altenburger

Nuclease cleavage of chromatin at 100-nucleotide pair intervals

Digestion of mouse liver nuclei with DNase II leads to a novel cleavage pattern with a 100-nucleotide pair periodicity. From chromatin, this pattern or the standard 200-nucleotide pair repeat can be produced depending on the ionic conditions. The results are interpreted by assuming different conformational states of the nuclear material, including condensed and extended forms.

THREE LEVELS OF CHROMATIN STRUCTURE

Abstract Experiments of our group on the three levels of chromatin structure are described. Special emphasis is given to the digestion of mouse liver chromatin by DNAase II. The conditions of DNAase II cleavage at either 200 bp or 100 bp intervals are examined. Histone H1 is required for cleavage in the 100 bp mode. The implications of the findings for chromatin structure and especially elements of superstructure are discussed.

STUDIES ON CHROMATIN STRUCTURE BY NUCLEASE DIGESTION

ABSTRACT Evidence is presented from late digests of mouse liver nuclei with micrococcal nuclease to indicate that a small fraction of this chromatin is organized in a 170 nucleotide Pair rather than the standard 200 nucleotide Pair periodicity. Chicken erythrocyte nuclei are cleaved by DNAase II in very much the same way as mouse liver nuclei. Conditions exist for cleaving chicken erythrocyte chromatin with DNAase II either at approximately 105 or at 210 nucleotide pair intervals. A comparison of the resulting DNA patterns shows characteristic differences also in the subnucleosomal range. The effect of these digestion conditions on the nucleolytic degradation of nucleosome core particles from mouse liver chromatin is described.