MOLECULAR DEVELOPMENTAL NEUROBIOLOGY
Research Focus
 The
laboratory's long-term research interest is the study of post-transcriptional
gene regulation in the vertebrate nervous system, and in particular, how the
metabolism of pre-mRNA and mRNA are controlled in neurons. The precise control
of protein expression is absolutely critical in biology, and the key decisions
about which genes are turned on or off at any one moment control the proper
growth and maturation of an organism during development, and are responsible
for the organism's homeostasis and proper response to environmental changes
as an adult. Many gene expression programs are highly complex and controlled
by regulating transcription of individual genes.
A current focus of the lab is examining the developmental role of the Hu family
of RNA binding proteins. In most vertebrates, there are four family members,
HuA, which is ubiquitously expressed, and three neuron-specific proteins, HuB,
HuC and HuD. Lab members are using a variety of biochemical and cell biological
methods to understand Hu protein function; these studies are complemented by
several lab projects that are attempting to address the functional role of the
Hu proteins during early development in the model vertebrate Danio rerio (zebrafish).
Identifying the RNA targets of the Hu proteins
At present, a key focus of the lab is to identify the RNA targets
of the Hu proteins at various stages of embryonic development. As sequence-specific
RNA binding proteins (RBPs), the Hu proteins are hypothesized to play a role
in the post-transcriptional regulation of a number of mRNAs, and previous studies
of the Hu proteins have indicated roles for the proteins in both nuclear export
and mRNA stabilization.
 We
have developed a novel technique in the laboratory that allows the identification
of genuine, in vivo RNA targets for any chosen RNA binding protein. In brief,
the fundamental principle of the method, termed "CLIP" is the use
of UV photocrosslinking to "freeze" RNA-protein interactions in fresh
brain tissue. These stable complexes can be purified and the RNA sequence surrounding
the site of crosslinking identified by sequencing; thus both the identity of
the mRNA and the site of interaction with the RNA binding protein are known
using the CLIP methodology.
We have identified a number of putative mRNA targets of the neuronal Hu proteins,
and we are currently attempting to validate these RNA-protein interactions in
the context of the zebrafish embryo. Furthermore, we we would like to determine
if the phenotypes seen during under- or over-expression of the neuronal Hu proteins
can be attributed to their regulation of a small number of key mRNA substrates
identified by the CLIP photocrosslinking method.
Recent publications
Collaborators
- Dr Eldon Ball, Australian National University,
Research School of Biological Sciences. Expression studies of neuronal RNA
binding proteins in cnidarians
- Dr. Simon Koblar, School of Molecular and Biomedical
Science, University of Adelaide, co-organise the School's neuroscience journal
club
- Dr. Joel McKay, School of Molecular and Microbial Biosciences, Sydney, Australia,
using in vitro selection methods to discover novel RNA ligands
- Dr Robert Darnell, The Rockefeller University, New York, NY, USA, investigations
of mice lacking the Hu family of neuronal RNA binding proteins
Publications (since 2000)
Jensen, K.B., Darnell R.B . (2006). CLIP: Cross-Linking and ImmunoPrecipitation
of in vivo RNA targets of RNA binding proteins book chapter in: RNA-Protein
Interactions Oxford University Press, 2006
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