[Abstract Title]. - Society for Neuroscience

1 Neurol., Beth Israel Deaconess Med. Ctr., Boston, MA; 2 Physiol. and Neurobio., Univ. of
Connecticut, Storrs, CT
Abstract: We have previously reported that disruption of candidate dyslexia susceptibility gene
(CDSG) homolog function in the rat results in neuronal migration disorders. Most recently, we
have shown that knockdown of Dyx1c1 and Dcdc2 function by in utero electroporation of short
hairpin RNAs (shRNAs) targeted against these genes causes abnormal migration, cortical
malformations and changes in neuronal morphology (Cereb Cortex, 17:2562,2007;
Neuroscience, 152:723, 2008). Here we examine the postnatal phenotype resulting from
embryonic disruption of another CDSG, KIAA0319, on neuronal migration and dendritic
morphology of neocortical neurons.
Embryos from pregnant rats (E16) were divided into four groups: Group 1 consisted of rats that
were co-transfected with plasmids encoding short hairpin RNA (shRNA) targeted against
Kiaa0319 along with eGFP. Group 2 was co-transfected with bicistronic plasmids encoding
eGFP and the KIAA0319 protein, and with mRFP plasmids while Group 3 was co-transfected
with Kiaa0319 shRNA, KIAA0319 overexpression-eGFP and mRFP. Group 4 was transfected
with a scrambled version of the Kiaa0319 shRNA. Mothers were also injected with BrdU at E18.
Animals were sacrificed at P21 and their brains were removed, cut in the coronal plane, and a 1in-10
series of sections stained with Thionin. Adjacent series of sections were processed for
immunohistochemical detection of eGFP, mRFP, BrdU, and the laminar markers Cux1, Foxp2
and/or Ctgf. The position of transfected neurons was charted using Neurolucida, and a migration
distance analysis performed. The dendritic trees from at least 45 neurons in each condition were
traced and quantified using Neurolucida.
Qualitative analysis revealed severe neuronal migration disorders in those rats embryonically
transfected with shRNA targeted against Kiaa0319, including large white matter heterotopias.
These heterotopias contained shRNA-transfected neurons as well as a number of non-transfected
neurons, suggesting that there are non-cell autonomous effects of shRNA transfection. Many of
the neurons in the heterotopias were Cux-1 and BrdU-positive, indicating misplaced layer 2-3
neurons. Taken together, these results support the contention that there are both cell- and noncell-autonomous
effects of embryonic CDSG shRNA electroporation.
Disclosures: V.J. Peschansky, None; T.J. Burbridge, None; A.J. Volz, None; C.G. Fiondella,
None; J.J. LoTurco, None; A.M. Galaburda, None; G.D. Rosen, None.
Poster
249. Dyslexia, SLI, and Other Disorders of Cognition and Behavior
Time: Sunday, November 16, 2008, 1:00 pm - 5:00 pm
Program#/Poster#: 249.3/U22
Topic: C.05.d. ADHD, SLI, dyslexia and other specific disorders of neurobehavior