Current Biology,
Journal Year:
2025,
Volume and Issue:
unknown
Published: April 1, 2025
Birds
possess
the
most
complex
photoreceptor
system
among
vertebrates,
with
one
rod
and
six
cone
types,
including
four
single
cones
(violet,
blue,
green,
red)
two
constituent
cells
of
double
(DC-P
DC-A).
The
evolutionary
relationships
avian
photoreceptors
to
those
other
vertebrate
taxa
have
not
been
systematically
explored.
Here,
we
perform
single-cell
RNA
sequencing
(scRNA-seq)
on
retinas
newly
hatched
chickens
trace
cell-type
homologies
across
species.
Analysis
differentially
expressed
transcription
factors
(TFs)
suggests
that
rods
types
correspond
cognate
cell
in
fish
placental
mammals,
whereas
a
distinct
origin.
We
propose
DC-P
arose
from
an
ancestral
red
cone,
as
revealed
by
expression
fate
determinants
thyroid
hormone
receptor
β
(THRB)
SAMD7,
DC-A
may
arisen
blue
suggested
TFs
FOXQ2
SKOR1.
These
signatures
are
shared
green
anole
lizard
(Anolis
carolinensis),
suggesting
conservation
throughout
Sauropsida.
Consistent
our
hypothesis,
CRISPR-mediated
knockout
THRB
causes
loss
DC-P,
but
DC-A,
appearance
supernumerary
cones,
suggestive
direct
transfating.
Furthermore,
cis-regulatory
analysis
separate
enhancers
control
opsin
consistent
origins.
Taken
together,
studies
suggest
origins
respectively.
Vision
is
the
primary
sensory
function
for
most
animals
and
also
a
sensitive
toxic
target
of
environmental
pollutants.
A
new
class
organophosphate
flame
retardants
(OPFRs)
termed
emerging
OPFRs
(eOPFRs)
with
limited
toxicological
information
rapidly
developed
into
substitutes
traditional
OPFRs.
In
this
study,
we
investigated
visual
toxicity
triphenyl
phosphate
(TPHP,
one
OPFR)
cresyl
diphenyl
(CDP,
on
zebrafish
larvae
at
environmentally
relevant
concentrations
(3
30
nM).
After
5
days
exposure,
an
opposite
was
found
between
two
OPFRs,
manifested
in
light
perception
gene
expressions
opsins.
CDP
caused
weak
reaction
to
overall
inhibition
opsin
expression
(0.7-
0.8-fold)
larvae,
while
TPHP
tended
stimulate
these
events
(1.2-
2.4-fold).
Besides,
identified
key
transcription
factor,
tbx2a,
that
significantly
disrupted
both
OPFRs'
exposure.
The
differing
ways
which
bind
Tbx2a
may
be
reason
behind
their
effects.
These
findings
provided
clues
mechanisms
revisited
question
regarding
safe
those
contaminants.
Nature Communications,
Journal Year:
2025,
Volume and Issue:
16(1)
Published: March 25, 2025
Cone
photoreceptors
assemble
to
form
a
regular
mosaic
pattern
in
vertebrate
retinas.
In
zebrafish,
four
distinct
spectral
cone
types
(red,
green,
blue,
and
ultraviolet),
lattice-like
pattern.
However,
the
mechanism
of
formation
has
been
unknown.
Here
we
show
that
Down
Syndrome
Cell
Adhesion
Molecule
b
(Dscamb)
regulates
especially
via
red-cone
spacing.
During
photoreceptor
differentiation,
newly
formed
cones
extend
filopodium-like
processes
laterally
apical
surfaces
neighboring
cones.
Interestingly,
red
filopodia,
but
promptly
retract
them
when
they
meet
their
own
type,
suggesting
filopodium-mediated,
homotypic
recognition
self-avoidance.
This
self-avoidance
is
compromised
zebrafish
dscamb
mutants,
leading
abnormal
clustering
subsequent
disruption
Thus,
filopodium-mediated
spacing
same
type
depends
on
Dscamb
essential
for
zebrafish.
retina.
The
authors
report
(DSCAM)
mediates
between
PLoS Biology,
Journal Year:
2025,
Volume and Issue:
23(5), P. e3003157 - e3003157
Published: May 7, 2025
Vertebrate
photoreceptors
have
been
studied
for
well
over
a
century,
but
fixed
nomenclature
referring
to
orthologous
cell
types
across
diverse
species
has
lacking.
Instead,
variably—and
often
confusingly—named
according
morphology,
presence/absence
of
‘rhodopsin’,
spectral
sensitivity,
chromophore
usage,
and/or
the
gene
family
opsin(s)
they
express.
Here,
we
propose
unified
vertebrate
rods
and
cones
that
aligns
with
naming
systems
other
retinal
classes
is
based
on
photoreceptor
type’s
putative
evolutionary
history.
This
classification
informed
by
functional,
anatomical,
developmental,
molecular
identities
neuron
as
whole,
including
expression
deeply
conserved
transcription
factors
required
development.
The
proposed
names
will
be
applicable
all
vertebrates
indicative
widest
possible
range
properties,
their
postsynaptic
wiring,
hence
allude
common
species-specific
roles
in
vision.
Furthermore,
system
open-ended
accommodate
future
discovery
as-yet
unknown
types.
Proceedings of the National Academy of Sciences,
Journal Year:
2024,
Volume and Issue:
121(47)
Published: Nov. 12, 2024
The
role
of
transcription
factors
in
photoreceptor
gene
regulation
is
fairly
well
understood,
but
knowledge
the
cell-type-specific
function
transcriptional
cofactors
remains
incomplete.
Here,
we
show
that
corepressor
samd7
promotes
rod
differentiation
and
represses
short-wavelength
cone
genes
long-wavelength
cones
zebrafish.
In
−/−
retinas,
red
are
transformed
into
hybrid
red/ultraviolet
(UV)
cones,
green
absent,
number
blue
approximately
doubled,
rods
greatly
reduced.
We
also
find
mouse
Samd7
S-opsin
expression
dorsal
M-cones—analogous
to
its
repressing
UV
zebrafish
cones.
Thus,
plays
a
key
ensuring
appropriate
patterns
subtypes
both
mice.
bioRxiv (Cold Spring Harbor Laboratory),
Journal Year:
2024,
Volume and Issue:
unknown
Published: Oct. 10, 2024
Abstract
Vertebrate
vision
is
accomplished
by
two
phenotypically
distinct
types
of
photoreceptors
in
the
retina:
saturation-resistant
cones
for
detection
bright
light
and
highly
sensitive
rods
dim
conditions
[1].
The
current
dogma
that,
during
development,
all
vertebrates
initially
feature
a
cone-dominated
retina,
are
added
later
[2,
3].
By
studying
ontogeny
three
species
deep-sea
fishes,
we
show
that
their
larvae
express
cone-specific
genes
with
rod-like
morphologies.
Through
these
fishes
either
retain
this
cone
retina
(
Maurolicus
mucronatus
)
or
switch
to
true
rod
expression
rod-specific
transcription
factors
Vinciguerria
mabahiss
Benthosema
pterotum
).
In
contrast
most
marine
which
inhabit
upper
layer
open
ocean,
occur
deeper,
exposing
them
dimmer
environment
[4–7].
Spectral
maxima
predictions
from
molecular
dynamics
simulations
environmental
estimations
suggest
using
transmuted
combine
characteristics
both
maximises
visual
performance
conditions.
Our
findings
provide
molecular,
morphological,
functional
evidence
evolution
an
alternative
developmental
pathway
vertebrate
vision.
Frontiers in Cellular Neuroscience,
Journal Year:
2023,
Volume and Issue:
17
Published: July 14, 2023
Understanding
how
photoreceptor
genes
are
regulated
is
important
for
investigating
retinal
development
and
disease.
While
much
known
about
gene
regulation
in
cones,
the
mechanism
by
which
tandemly-replicated
opsins,
such
as
human
long
wavelength-sensitive
middle
differentially
remains
elusive.
In
this
study,
we
aimed
to
further
our
understanding
of
transcriptional
heterogeneity
cones
that
express
opsins
differential
expression
using
zebrafish,
lws1
lws2.
We
performed
bulk
single
cell
RNA-Seq
LWS1
LWS2
evaluated
patterns
selected
interest
multiplex
fluorescence
situ
hybridization,
used
exogenous
thyroid
hormone
(TH)
treatments
test
potential
control
hormone:
a
potent,
endogenous
regulator
lws2
expression.
Our
studies
indicate
additional
differences
beyond
opsin
exist
between
cones.
Bulk
results
showed
95
transcripts
enriched
186
(FC
>
2,
FDR
<
0.05).
hybridization
also
reveal
underlying
within
lws1-
lws2-expressing
populations.
This
evident
mature
revealed
responses
TH
treatments.
found
some
evidence
coordinate
lws
other
vs.
well
not
mediated
TH.
The
likely
controlled
multiple
signals,
including
