NTU Undergraduates' research April 2014 - Biosciences | Página 25

Expression of Activity-Regulated cytoskeletal protein in different
tissues.
Lauren E. Allen

Abstract
The activity-regulated cytoskeletal protein (Arc) gene was first identified in the brain for its role in memory
consolidation and multiple forms of synaptic plasticity. Many proteins within the brain are involved in synaptic
plasticity, however it is only a few that show the precise regulation of expression as in Arc, making this highly versatile
and tuned system interesting to observe. It is known that the induction of neuronal activity stimulates the expression
of Arc within the brain and the presence of the protein is known for its role in the functional sperm unit, as well as its
involvement in capacitation. Here it is attempted to determine the expressional level of Arc in different tissues, using
a cloning technique (RT-PCR) to identify the novel IEG’s cDNA. Accordingly, this paper has confirmed the presence of
Arc expression in: brain, bone, testis, kidney, intestine, liver, lung, eye, skin and leg muscle. As expected, a higher
expression level was observed in the brain and testis. The eye, in comparison to other tissues also showed increased
expression, but due to its involvement with synaptic plasticity, glutamate receptors (NMDAR and AMPAR) as seen in
the brain and its classification of the retina as brain tissue suggests why. A higher expressional level in both lung and
intestine tissue implies a link between Arc and the specialised role of mucus secretion and mucus secreting cells. Arc’s
key role in actin cytoskeleton dynamics associate d with the regulation of memory consolidation and homeostatic
plasticity, as well as differentiation, germ cell development, motility and capitation in sperm, gives reason to suggest
its presence in peripheral tissues. This coextension with actin and the known intracellular distribution of Arc supports
a causal role in its expression on a systemic level. The main conclusion garnered from this work is that Arc expression
is not confined to the brain and testis but is present on a systemic level.
Keywords: Activity-regulated cytoskeletal protein (Arc), Arg 3.1, synaptic plasticity, LTP, expression, NMDA, AMPA.