With no explanation, label each line with "O", "other-biologything", "art-broadcastprogram", "art-film", "art-music", "art-other", "art-painting", "art-writtenart", "building-airport" or "building-hospital" preceded by ":".
In
the
realm
of
gene
silencing
,
Polycomb
repressive
complex
2
,
one
of
two
classes
of
the
Polycomb
group
(
PcG
)
family
of
proteins
,
catalyzes
the
di-
and
tri-methylation
of
histone
H3
lysine
27
(
H3K27me2/me3
)
.
In:O
the:O
realm:O
of:O
gene:O
silencing:O
,:O
Polycomb:other-biologything
repressive:other-biologything
complex:other-biologything
2:other-biologything
,:O
one:O
of:O
two:O
classes:O
of:O
the:O
Polycomb:other-biologything
group:other-biologything
(:O
PcG:other-biologything
):O
family:O
of:O
proteins:O
,:O
catalyzes:O
the:O
di-:O
and:O
tri-methylation:O
of:O
histone:other-biologything
H3:other-biologything
lysine:other-biologything
27:other-biologything
(:O
H3K27me2/me3:other-biologything
):O
.:O