Role of Polycomb Proteins in Gene Description,
Stem Cells and Human Diseases,
by Luciano Di Croce, from the Gene
Regulation, Stem cell, and Cancer Department,
ICREA, and Center for Genomic
Regulation, Barcelona, Spain.
The DNA of eukaryotic cells is
organized in chromatin fibers,
where the nucleosome forms
the basic repeating unit.
Each nucleosome comprises 147 base
pairs of DNA, which is wrapped
in 1.8 elegant turn around an
octamer of four highly [INAUDIBLE]
conserved histone protein, which are
histone H two A, histone H two B,
histone H three, and histone H four.
These four structure, which is
often called as 11 nanometer fibers.
The histone H1 lines to deliver DNA
between two addition nucleosomes,
causing further compaction
of the chromatin fibers
into higher order structure,
often refer as a solenoid or as 30
The analyses of the crystal
structure of the nucleosome,
which was solved in 1998 by the
group of Luger and Richmond,
reveal that on terminal a part of the histone tail
are flexible and protrude
outside from the nucleosome core.
The histone tail
undergoes a large number
of post-translational modifications.