bioRxiv (Cold Spring Harbor Laboratory),
Journal Year:
2023,
Volume and Issue:
unknown
Published: Sept. 17, 2023
Multimodal,
single-cell
genomics
technologies
enable
simultaneous
capture
of
multiple
facets
DNA
and
RNA
processing
in
the
cell.
This
creates
opportunities
for
transcriptome-wide,
mechanistic
studies
cellular
heterogeneous
cell
types,
with
applications
ranging
from
inferring
kinetic
differences
between
cells,
to
role
stochasticity
driving
heterogeneity.
However,
current
methods
determining
types
or
'clusters'
present
multimodal
data
often
rely
on
ad
hoc
independent
treatment
modalities,
assumptions
ignoring
inherent
properties
count
data.
To
interpretable
consistent
cluster
determination
data,
we
meK-Means
(mechanistic
K-Means)
which
integrates
modalities
learns
underlying,
shared
biophysical
states
through
a
unifying
model
transcription.
In
particular,
demonstrate
how
can
be
used
cells
unspliced
spliced
mRNA
modalities.
By
utilizing
causal,
physical
relationships
underlying
these
identify
transcriptional
kinetics
across
induce
observed
gene
expression
profiles,
provide
an
alternative
definition
governing
parameters
processes.
Biophysical Journal,
Journal Year:
2023,
Volume and Issue:
123(1), P. 4 - 30
Published: Oct. 27, 2023
The
snapshot
distribution
of
mRNA
counts
per
cell
can
be
measured
using
single-molecule
fluorescence
in
situ
hybridization
or
single-cell
RNA
sequencing.
These
distributions
are
often
fit
to
the
steady-state
two-state
telegraph
model
estimate
three
transcriptional
parameters
for
a
gene
interest:
synthesis
rate,
switching
on
rate
(the
state
being
active
state),
and
off
rate.
This
assumes
no
extrinsic
noise,
i.e.,
do
not
vary
between
cells,
thus
estimated
understood
as
approximating
average
values
population.
accuracy
this
approximation
is
currently
unclear.
Here,
we
develop
theory
that
explains
size
sign
estimation
bias
when
inferring
from
data
standard
model.
We
find
specific
signatures
depending
source
noise
(which
parameter
most
variable
across
cells)
mode
activity.
If
expression
bursty
then
population
averages
all
overestimated
if
rate;
underestimation
occurs
both
overestimation
occur
some
tend
infinity
approaches
critical
threshold.
In
contrast
bursty,
cases
mean
burst
(ratio
rate)
while
frequency
underestimated.
covariance
matrix
sequencing
use
together
with
our
correct
published
estimates
mammalian
genes.
Proceedings of the National Academy of Sciences,
Journal Year:
2024,
Volume and Issue:
121(18)
Published: April 26, 2024
RNA
velocity
estimation
is
a
potentially
powerful
tool
to
reveal
the
directionality
of
transcriptional
changes
in
single-cell
RNA-sequencing
data,
but
it
lacks
accuracy,
absent
advanced
metabolic
labeling
techniques.
We
developed
an
approach,
bioRxiv (Cold Spring Harbor Laboratory),
Journal Year:
2023,
Volume and Issue:
unknown
Published: Jan. 14, 2023
Abstract
We
motivate
and
present
biVI
,
which
combines
the
variational
autoencoder
framework
of
scVI
with
biophysically
motivated,
bivariate
models
for
nascent
mature
RNA
distributions.
While
previous
approaches
to
integrate
bimodal
data
via
ignore
causal
relationship
between
measurements,
biophysical
processes
that
give
rise
observations.
demonstrate
through
simulated
benchmarking
captures
cell
type
structure
in
a
low-dimensional
space
accurately
recapitulates
parameter
values
copy
number
On
biological
data,
provides
scalable
route
identifying
mechanisms
underlying
gene
expression.
This
analytical
approach
outlines
generalizable
strateg
treating
multimodal
datasets
generated
by
high-throughput,
single-cell
genomic
assays.
The Journal of Chemical Physics,
Journal Year:
2024,
Volume and Issue:
160(6)
Published: Feb. 14, 2024
Stochastic
differential
equations
(SDEs)
are
a
powerful
tool
to
model
fluctuations
and
uncertainty
in
complex
systems.
Although
numerical
methods
have
been
designed
simulate
SDEs
effectively,
it
is
still
problematic
when
solutions
may
be
negative,
but
application
problems
require
positive
simulations.
To
address
this
issue,
we
propose
balanced
implicit
Patankar-Euler
ensure
simulations
of
SDEs.
Instead
considering
the
addition
terms
explicit
existing
methods,
attempt
deletion
possible
negative
from
maintain
positivity
The
include
negative-valued
drift
potential
diffusion
terms.
proposed
method
successfully
addresses
issue
divisions
with
very
small
denominators
our
recently
stochastic
Patankar
method.
Stability
analysis
shows
that
has
much
better
stability
properties
than
composite
Four
SDE
systems
used
examine
effectiveness,
accuracy,
convergence
methods.
Numerical
results
suggest
an
effective
efficient
approach
any
appropriate
stepsize
simulating
biological
regulatory
Journal of The Royal Society Interface,
Journal Year:
2025,
Volume and Issue:
22(225)
Published: April 1, 2025
The
dynamics
of
gene
expression
are
stochastic
and
spatial
at
the
molecular
scale,
with
messenger
RNA
(mRNA)
transcribed
specific
nuclear
locations
then
transported
to
boundary
for
export.
Consequently,
distributions
these
molecules
encode
their
underlying
dynamics.
While
mechanistic
models
counts
have
revealed
numerous
insights
into
expression,
they
largely
neglected
now-available
subcellular
resolution
down
individual
molecules.
Owing
technical
challenges
inherent
in
processes,
tools
studying
patterns
still
limited.
Here,
we
introduce
a
model
mRNA
two-state
(telegraph)
transcriptional
Observations
can
be
concisely
described
as
following
Cox
process
driven
by
stochastically
switching
partial
differential
equation.
We
derive
analytical
solutions
demographic
moments
validate
them
simulations.
show
that
distribution
accurately
approximated
Poisson-beta
tractable
parameters,
even
complex
This
observation
allows
efficient
parameter
inference
demonstrated
on
synthetic
data.
Altogether,
our
work
adds
progress
towards
new
frontier
inferring
from
static
snapshot
Nucleic Acids Research,
Journal Year:
2025,
Volume and Issue:
53(7)
Published: March 31, 2025
Bursty
gene
expression
is
characterized
by
two
intuitive
parameters,
burst
frequency
and
size,
the
cell-cycle
dependence
of
which
has
not
been
extensively
profiled
at
transcriptome
level.
In
this
study,
we
estimate
parameters
per
allele
in
G1
G2/M
phases
for
thousands
mouse
genes
fitting
mechanistic
models
to
messenger
RNA
count
data,
obtained
sequencing
single
cells
whose
position
inferred
using
a
deep-learning
method.
We
find
that
upon
DNA
replication,
median
approximately
halves,
while
size
remains
mostly
unchanged.
Genome-wide
distributions
parameter
ratios
between
are
broad,
indicating
substantial
heterogeneity
transcriptional
regulation.
also
observe
significant
negative
correlation
ratios,
suggesting
regulatory
processes
do
independently
control
parameters.
show
accurately
must
explicitly
account
copy
number
variation
extrinsic
noise
due
coupling
transcription
cell
age
across
cycle,
but
corrections
technical
imperfect
capture
molecules
experiments
less
critical.
bioRxiv (Cold Spring Harbor Laboratory),
Journal Year:
2022,
Volume and Issue:
unknown
Published: June 12, 2022
Abstract
We
present
the
Python
package
Monod
for
analysis
of
single-cell
RNA
sequencing
count
data
through
biophysical
modeling.
naturally
“integrates”
unspliced
and
spliced
matrices,
provides
a
route
to
identifying
studying
differential
expression
patterns
that
do
not
cause
changes
in
average
gene
expression.
The
framework
is
open-source
modular,
may
be
extended
more
sophisticated
models
variation
further
experimental
observables.
can
installed
from
command
line
using
pip
install
monod.
source
code
available
maintained
at
https://github.com/pachterlab/monod
.
A
separate
repository,
which
contains
sample
notebooks
with
,
accessible
https://github.com/pachterlab/monod_examples/
Structured
documentation
tutorials
are
hosted
https://monod-examples.readthedocs.io/