Chromatin
conformation
regulates
gene
expression
and
thus,
constant
remodeling
of
chromatin
structure
is
essential
to
guarantee
proper
cell
function.
To
gain
insight
into
the
spatiotemporal
organization
genome,
we
use
high-density
photoactivated
localization
microscopy
deep
learning
obtain
temporally
resolved
super-resolution
images
in
living
cells.
In
combination
with
high-resolution
dense
motion
reconstruction,
find
elongated
~45-
90-nm-wide
"blobs."
A
computational
model
suggests
that
these
blobs
are
dynamically
associating
fragments
close
physical
genomic
proximity
adopt
topologically
associated
domain-like
interactions
time-average
limit.
Experimentally,
found
exhibits
a
correlation
over
~4
μm
space
tens
seconds
time,
while
dynamics
correlated
~6
last
40
s.
Notably,
closely
related,
which
may
constitute
mechanism
grant
access
regions
high
local
concentration.
Molecular Cell,
Год журнала:
2020,
Номер
78(2), С. 236 - 249.e7
Опубликована: Фев. 25, 2020
The
formation
of
silenced
and
condensed
heterochromatin
foci
involves
enrichment
protein
1
(HP1).
HP1
can
bridge
chromatin
segments
form
liquid
droplets,
but
the
biophysical
principles
underlying
compartmentalization
in
cell
nucleus
are
elusive.
Here,
we
assess
mechanistically
relevant
features
pericentric
compaction
mouse
fibroblasts.
We
find
that
(1)
has
only
a
weak
capacity
to
droplets
living
cells;
(2)
size,
global
accessibility,
independent
HP1;
(3)
lack
separated
pool;
(4)
toggle
between
two
"digital"
states
depending
on
presence
strong
transcriptional
activator.
These
findings
indicate
resemble
collapsed
polymer
globules
percolated
with
same
nucleoplasmic
as
surrounding
euchromatin,
which
implications
for
our
understanding
its
functional
consequences.
While
long
non-coding
RNA
(lncRNA)
genes
have
attracted
a
lot
of
attention
in
the
last
decade,
focus
regarding
their
mechanisms
action
has
been
primarily
on
product
these
genes.
Recent
work
several
lncRNAs
demonstrates
that
not
only
is
produced
species
important,
but
also
transcription
lncRNA
locus
alone
can
regulatory
functions.
Like
functions
transcripts,
underlie
genome-based
are
varied.
Here
we
highlight
some
examples
and
provide
an
outlook
how
functional
gene
be
determined.
