Genes & Development,
Год журнала:
2016,
Номер
30(16), С. 1866 - 1880
Опубликована: Авг. 15, 2016
A
defining
feature
of
heterochromatin
is
methylation
Lys9
histone
H3
(H3K9me),
a
binding
site
for
protein
1
(HP1).
Although
H3K9
methyltransferases
and
HP1
are
necessary
proper
structure,
the
specific
contribution
to
function
animal
development
unknown.
Using
our
recently
developed
platform
engineer
genes
in
Drosophila,
we
generated
H3K9R
mutant
flies,
separating
functions
nonhistone
substrates
methyltransferases.
Nucleosome
occupancy
HP1a
at
pericentromeric
markedly
decreased
mutants.
Despite
these
changes
chromosome
architecture,
small
percentage
mutants
complete
development.
Consistent
with
this
result,
expression
most
protein-coding
genes,
including
those
within
heterochromatin,
similar
between
controls.
In
contrast,
exhibit
increased
open
chromatin
transcription
from
piRNA
clusters
transposons,
resulting
transposon
mobilization.
Hence,
silencing
major
developmental
H3K9.
Many
eukaryotic
cells
can
respond
to
transient
environmental
or
developmental
stimuli
with
heritable
changes
in
gene
expression
that
are
associated
nucleosome
modifications.
However,
it
remains
uncertain
whether
modified
nucleosomes
play
a
causal
role
transmitting
such
epigenetic
memories,
as
opposed
controlling
merely
reflecting
transcriptional
states
inherited
by
other
means.
Here,
we
provide
vivo
evidence
H3K27
trimethylated
nucleosomes,
once
established
at
repressed
Genetics,
Год журнала:
2017,
Номер
206(4), С. 1699 - 1725
Опубликована: Авг. 1, 2017
Abstract
Polycomb
group
(PcG)
and
Trithorax
(TrxG)
genes
encode
important
regulators
of
development
differentiation
in
metazoans.
These
two
groups
were
discovered
Drosophila
by
their
opposing
effects
on
homeotic
gene
(Hox)
expression.
PcG
collectively
behave
as
genetic
repressors
Hox
genes,
while
the
TrxG
are
necessary
for
HOX
expression
or
function.
Biochemical
studies
showed
that
many
proteins
present
protein
complexes,
repressive
complexes
1
2,
which
repress
transcription
via
chromatin
modifications.
activate
a
variety
mechanisms.
Here
we
summarize
large
body
biochemical
experiments
these
genes.
Genes & Development,
Год журнала:
2015,
Номер
29(14), С. 1487 - 1492
Опубликована: Июль 15, 2015
Histone
H2A
monoubiquitylation
(H2Aub)
is
considered
to
be
a
key
effector
in
transcriptional
repression
by
Polycomb-repressive
complex
1
(PRC1).
We
analyzed
Drosophila
with
point
mutation
the
PRC1
subunit
Sce
that
abolishes
its
ubiquitylase
activity
or
mutations
and
H2Av
residues
ubiquitylated
PRC1.
H2Aub
essential
for
viability
required
efficient
histone
H3
Lys27
trimethylation
PRC2
early
embryogenesis.
However,
H2Aub-deficient
animals
fully
maintain
of
target
genes
do
not
show
phenotypes
characteristic
Polycomb
group
mutants.
thus
represses
canonical
independently
H2Aub.
Genes & Development,
Год журнала:
2016,
Номер
30(15), С. 1683 - 1697
Опубликована: Авг. 1, 2016
For
more
than
three
decades,
investigators
have
sought
to
identify
the
precise
locations
where
DNA
replication
initiates
in
mammalian
genomes.
The
development
of
molecular
and
biochemical
approaches
start
sites
(origins)
based
on
presence
defining
characteristic
intermediates
at
specific
loci
led
identification
only
a
handful
origins.
limited
number
identified
origins
prevented
comprehensive
exhaustive
search
for
conserved
genomic
features
that
were
capable
specifying
replication.
More
recently,
adaptation
origin-mapping
assays
genome-wide
has
tens
thousands
throughout
genomes,
providing
an
unprecedented
opportunity
both
genetic
epigenetic
define
regulate
their
distribution
utilization.
Here
we
summarize
recent
advances
our
understanding
how
primary
sequence,
chromatin
environment,
nuclear
architecture
contribute
dynamic
selection
activation
across
diverse
cell
types
developmental
stages.
