A unified phylogeny-based nomenclature for histone variants

The lack of a consistent naming convention
for histone variants has led to much confusion for histone researchers in
recent years, at a time when genome sequencing has become routine and the
number of known variants has greatly increased. This has led to problems
concerning the similarity of names and incorrect attributions of orthology or
common function.

Faced with this challenge, attendees of the
EMBO Workshop on Histone Variants held last year have developed consistent but
flexible naming rules that are both informative and database-searchable. The
comprehensive review, published in Epigenetics
& Chromatin
, proposes a new, unified, phylogeny-based nomenclature for
histone variants.

The project, led
by Paul Talbert and Steven Henikoff of the Howard Hughes Medical Institute in
Seattle, was the result of a community effort of researchers from 35 different
institutions worldwide, in response
to an urgent need to rationalize the currently inconsistent schemes for naming
histone variants.

Histones are
proteins that package DNA into structures called nucleosomes found in eukaryotic
nuclei. They are found in multigene families and may encode isoforms, commonly
referred to as histone variants, with different functions. Though the existence
of histone variants has been known since
the beginnings of histone research, the diversity of their various roles and
functions are still being discovered.

Building on current
usage, Talbert et al. propose a
nomenclature that uses a consistent system of punctuation that reflects
phylogenetic relationships among variant subtypes, making explicit the
evolutionary links that have been previously unclear. They also recommend using
organism-specific numbering, and separate letter suffixes for structurally
distinct groups of variants.

This powerfully effective scheme, based on the understanding that common
structures and functions reflect shared evolutionary history, should serve to
accommodate the ever-increasing rate of discoveries emerging from new genome
sequencing projects in the future

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