Breaking the traditional view: connecting histones regulate the length and shape of chromosomes

Human life depends on whether our cells can stuff 6-foot-long DNA into a 10-micron nucleus—the equivalent of stuffing a mile of rope in a green pea

Now, new research has determined a protein called junctional histone, which controls whether DNA is wound into long and thin chromosomes (consisting of many small loops) or short and thick chromosomes (consisting of fewer loops).

"Connected histones were once thought to affect only a small part of genetic material," said Rockefeller's Hironori Funabiki

Beyond "beads"

The genetic material is organized around nucleosomes, which are usually described as a string of beads, with a DNA "thread" wound around a central protein "bead"

The chromosomes of different species and cell types have different shapes, largely depending on the size of each chromatin ring

Scientists know that ring formation is at the core of the size and shape of chromosomes, but how various cells regulate this process to form larger or smaller rings remains a mystery

The new role of linkin

Funabiki and colleagues set out to solve this puzzle

A picture of a ring structure begins to emerge, linking histones at the core of this process

When high concentrations of connexin histones block chymosin, the protein complex produces fewer chromatin loops

Funabiki speculates that cells may have evolved the ability to adjust the length of chromosomes to speed up or slow down their growth

In the future, Funabiki's laboratory will explore whether linking histones play a similar role in influencing the size and shape of human chromosomes

DOI

10.