Despite the existence of certain differences between yeast and higher eukaryotic 
cells a considerable part of our knowledge on chromatin structure and function 
has been obtained by experimenting on Saccharomyces cerevisiae. One of the 
peculiarities of S. cerevisiae cells is the unusual and less abundant linker 
histone, Hho1p. Sparse is the information about Hho1p involvement in yeast 
higher-order chromatin organization. In an attempt to search for possible 
effects of Hho1p on the global organization of chromatin, we have applied 
Chromatin Comet Assay (ChCA) on HHO1 knock-out yeast cells. The results showed 
that the mutant cells exhibited highly distorted higher-order chromatin 
organization. Characteristically, linker histone depleted chromatin generally 
exhibited longer chromatin loops than the wild-type. According to the Atomic 
force microscopy data the wild-type chromatin appeared well organized in 
structures resembling quite a lot the "30-nm" fiber in contrast to HHO1 
knock-out yeast.