Salt-urea, sulfopropyl-sepharose, and covalent chromatography methods for histone isolation and fractionation.

The histones are essential basic proteins intimately involved in most DNA-templated processes. Thus, their purification and fractionation for analysis and their use for in vitro chromatin transactions are of fundamental importance for understanding their role in chromatin structure and regulation of DNA functions. Here are described three new protocols for histone isolation from undisturbed whole cells.

Pulling chromatin apart: Unstacking or Unwrapping?

Background: Understanding the mechanical properties of chromatin is an essential step towards deciphering the physical rules of gene regulation. In the past ten years, many single molecule experiments have been carried out, and high resolution measurements of the chromatin fiber stiffness are now available. Simulations have been used in order to link those measurements with structural cues, but so far no clear agreement among different groups has been reached.

Proteome analysis of protein partners to nucleosomes containing canonical H2A or the variant histones H2A.Z or H2A.X.

Although the existence of histone variants has been known for quite some time, only recently are we grasping the breadth and diversity of the cellular processes in which they are involved. Of particular interest are the two variants of histone H2A, H2A.Z and H2A.

Hho1p, the linker histone of Saccharomyces cerevisiae, is important for the proper chromatin organization in vivo.

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.

New nuclear partners for nucleosome assembly protein 1: unexpected associations.

Histone chaperones are important players in chromatin dynamics. They are instrumental in nucleosome assembly and disassembly and in histone variant exchange reactions that occur during DNA transactions. The molecular mechanisms of their action are not well understood and may involve interactions with various protein partners in the context of the nucleus.