Biochemistry
of Vision 
We
seek to understand how photoreceptors
function. Photoreceptors are
the cells in the eye that detect
and respond to light. We are
particularly interested in understanding
the mechanisms that permit these
cells to change their sensitivity
to light in response to changes
in background illumination and
to signals from an internal
twenty-four hour (circadian)
clock. These changes in sensitivity
are critical for normal vision,
allowing animals to see in both
bright and dim light. Our principal
experimental preparations are
the large photoreceptors of
the horseshoe crab Limulus
polyphemus. Sensitivity
changes in these cells in response
to both light and signals from
a circadian clock are particularly
robust.
Current
Projects
Much
of our effort during this past
year focused on understanding
the functions of a protein in
Limulus photoreceptors
called myosin III (myoIII) that
is rapidly modified by both
light and signals from the circadian
clock. The rapid modification
of existing proteins is a major
mechanism used by all cells
to quickly change their functions.
MyoIII is highly concentrated
in Limulus photoreceptors,
especially in the region responsible
for detecting light. Although
the functions of myoIII are
not understood, we speculate
that the modification of Limulus
myoIII we see contributes to
light-driven and clock-driven
changes in the photoreceptor’s
sensitivity to light. MyoIII
is related to the major protein
in muscles responsible for muscle
movement, and it may contribute
to the structure of the photoreceptor.
We have shown that myoIII can
modify itself and other proteins.
A major goal of ongoing research
is to identify the sites on
Limulus myoIII that
become modified by signals from
the circadian clock and by its
own activity. Precisely locating
these sites is critical for
understanding how the functions
of Limulus myoIII might
be changed by the circadian
clock. Major progress was made
this year toward identifying
these sites.
Another
goal is to identify other proteins
that are modified by myoIII.
This information may be key
to understanding myoIII’s
role in photoreceptors. We have
identified a number of potential
targets by reacting purified
myoIII with a variety of proteins
and peptides in vitro (in test
tubes). A future challenge will
be to determine whether the
targets we identify in vitro
are also modified by myoIII
in intact photoreceptors.
We have recently extended our
studies of myoIIIs to mice.
First discovered in the photoreceptors
of Limulus and fruit
flies, homologues of these myoIIIs
have recently been identified
in the photoreceptors of fish
and in the retinas of humans.
Other researchers cloned one
class of myoIII from mouse retinas
(myoIIIA) and we have cloned
a second class from these retinas
(myoIIIB). Thus, it is very
likely that myoIIIs are critical
for the function of all photoreceptors.
In
the coming year we will continue
our studies of myoIIIs in Limulus,
a model which provides an abundant
source of the least complex
form of myoIII, and in mice,
a model which enables us to
apply powerful genetic tools,
with the aim of determining
the functions of these proteins
in photoreceptors.
Personnel
Barbara-Anne
Battelle, Professor
Christiana Katti, Postdoctoral
Research Associate
Karen E. Kempler, Biological
Scientist
Selected
Publications
Battelle, B-A. (2006) The eyes of Limulus
polyphemus (Xiphosura, Chelicerata) and their afferent and
efferent projections. Arthropod Str. Devel. 35:1-14
Harzsch, S., Vilpoux, K., Blackburn, D. C., Platchetzki, D., Brown, N. L., Melzer,
R., Kempler, K.E., Battelle,B-A. (2006) Evolution of arthropod visual systems:
Development of the eyes and central visual pathways in the horseshoe crab Limulus
polyphemus Linnaeus, 1758 (Chelicerata, Xiphosura). Devel. Dynamics.
235:2641-2655.
Harzsch, S., Wildt, M., Battelle,
B., Waloszek, D. (2005) Immunohistochemical localization of neurotransmitters
in the nervous system of larval Limulus
polyphemus (Chelicerata, Xiphosura): evidence for a conserved
protocerebral architecture in Euarthropoda. Arthropod Str.
Devel. 34:327-342.
Sineschchekova, O.O., Cardasis, H.L.,
Severance, E.G., Smith, W.C., and Battelle, B-A. (2004) Sequential
phosphorylation of visual arrestin in intact Limulus photoreceptors:
Identification of a highly light-regulated site. Visual
Neuroscience. 21:715-724.
Dabdoub,
A., Jinks, R.N., Wang, Y., Battelle,
B-A. and Payne, R. (2003) Desensitization
of the photoresponse by protein
kinase C precedes rhabdomere
disorganization and endocytosis.
Visual Neuroscience
20: 241-248.
Dalal,
J.S., Jinks, R.N., Cacciatore,
C., Greenberg, R.M. and Battelle,
B-A. (2003) Limulus
opsins: diurnal regulation of
expression. Visual Neuroscience
20: 523-535.
Sacunas,
R.B., Papuga, M.O., Pearson,
Jr., A.C., Marjanovic, M., Stroope,
D.G., Weiner, W.W., Chamberlain,
S.C. and Battelle, B-A. (2002)
Multiple mechanisms of rhabdom
shedding in the lateral eye
of Limulus polyphemus.
J. Comp. Neurol. 449:26-42.
Battelle,
B-A. (2002) Circadian efferent
input to Limulus eyes:
Anatomy, circuitry and impact.
Microscopy Research and
Technique. 58:345-355.
Battelle,
B-A. and Hart, M.K. (2002) Histamine
metabolism in the visual system
of the horseshoe crab Limulus
polyphemus. Comparative
Biochemistry and Physiology
133:135-142.
Battelle,
B-A., Dabdoub, A., Malone, M.A.,
Andrews, A.W., Cacciatore, C.,
Calman, B.G., Smith, W.C., and
Payne, R. (2001) Immunocytochemical
localization of opsin, visual
arrestin, myosin III and calmodulin
in Limulus lateral eye
retinular cells and ventral
photoreceptors. J. Comp.
Neurol. 435:211-225.
Battelle,
B-A., Williams, C.D., Schremser-Berlin,
J-L. and Chelsi Cacciatore.
(2000). Regulation of arrestin
mRNA levels in Limulus
lateral eyes: Separate and combined
influences of circadian efferent
input and light. Visual Neuroscience
17:217-227.
Battelle,
B-A., Andrews, A.W., Kempler,
K.E., Edwards, S.C., and Smith,
S.C. (2000). Visual arrestin
in Limulus is phosphorylated
at multiple sites in the light
and in the dark. Visual Neuroscience
17: 813-822.
Battelle,
B-A., Williams, C.D., Schremser-Berlin,
J-L. and Chelsi Cacciatore (2000)
Regulation of arrestin mRNA
levels in Limulus lateral
eyes: Separate and combined
influences of circadian efferent
input and light. Visual
Neuroscience 17:217-227.
Battelle,
B-A., B.G. Calman and M.K. Hart.
(1999). Cellular distributions
and functions of histamine,
octopamine and serotonin in
the peripheral visual system,
brain and circumesophageal ring
of the horseshoe crab, Limulus
polyphemus. Microscopy
Research and Techniques.
44:70-80.
Chen,
F., Ukhanova, M., Thomas, D.,
Afshar, G., Tanda, S., Battelle,
B-A., and Payne, R. (1999) Molecular
cloning of a putative cyclic
nucleotide-gated ion channel
cDNA from Limulus polyphemus.
J. Neurochem. 72:461-471.
Battelle,
B-A., A.W. Andrews, B.G. Calman,
J.R. Sellers, R.M. Greenberg
and W.C. Smith. (1998). A myosin
III from Limulus eyes
is a clock-regulated phosphoprotein.
J. Neuroscience. 18:4548-4559.
Calman,
B.G., A.W. Andrews, H.M. Rissler,
S.C. Edwards, and B-A. Battelle.
(1996). Calcium/calmodulin-dependent
protein kinase II and arrestin
phosphorylation in Limulus
eyes. J. Photochem. Photobiol.
B: Biology. 35:33-44.
Smith,
W.C., R.M. Greenberg, B.G. Calman,
M.M. Hendrix, L. Hutchinson,
L.A. Donoso, and B-A. Battelle.
(1995). Isolation and expression
of an arrestin cDNA from the
horseshoe crab lateral eye.
J. Neurochem. 64: 1-13.
Smith,
W.C., D.A. Price, R.M. Greenberg,
and B-A. Battelle. (1993). Opsins
from the lateral eyes and ocelli
of the horseshoe crab, Limulus
polyphemus. Proc.
Natl. Acad Sci. USA 90:
6150-6154.
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