Distribution of linker DNA in relation to core DNA in H1 depleted nucleosomes

The mode of interaction of histone H1 with the nucleosome is governed by the relative distribution of the linker with respect to the core DNA. Preliminary experiments (Simpson, R.T. 1978, Biochemistry, 17, 5524-5531) and tentative models (Thoma, F. et al. (1979), J. Cell. Biol., 83, 403-427) suggest that part of the linker complete two full turns of DNA around the histone core, probably by adding 10 base pairs at each end of the core DNA. In the present study Exonuclease III has been utilized to digest the 3' ends of H1 depleted nucleosomes. (i.e. the 195 base pair particle). The analysis of the resulting DNA fragments under denaturing conditions shows that the whole linker is distributed symmetrically with respect to the core DNA.