When citing an abstract from the 2014 annual meeting please use the format below.

1677 Pages·2014·6.85 MB·English

by  Michele Appley

When citing an abstract from the 2014 annual meeting please use the format below.

[Authors]. [Abstract Title]. Program No. XXX.XX. 2014 Neuroscience Meeting Planner.
Washington, DC: Society for Neuroscience, 2014. Online.

2014 Copyright by the Society for Neuroscience all rights reserved. Permission to republish any
abstract or part of any abstract in any form must be obtained in writing by SfN office prior to
publication.
Poster

120. Mechanisms of Neuronal Cell Fate Acquisition
Location: Halls A-C
Time: Sunday, November 16, 2014, 8:00 AM - 12:00 PM
Program#/Poster#: 120.01/A1
Topic: A.02. Neurogenesis and Gliogenesis
Support: Johns Hopkins Brain Science Institute
Title: Control of hypothalamic neuronal specification and survival by the LIM homeodomain
factor Lhx6
Authors: *K. LIU, H. WANG, S. BLACKSHAW
Johns Hopkins Med. Inst., Baltimore, MD
Abstract: The LIM homeodomain family of transcription factors regulate many different
processes during brain development, including cell fate specification, neuronal migration and
connectivity. Lhx6, a member of this gene family, is expressed in a previously uncharacterized
subset of GABAergic neurons in the zona incerta and posterior hypothalamus in both embryonic
and postnatal hypothalamus. Lhx6 is required for the tangential migration of interneuron
precursors from the ventral telencephalon to the cortex and hippocampus, but is not required for
their survival. In contrast, we have found that hypothalamic Lhx6 neurons do not undergo
substantial tangential migration, but require Lhx6 for their survival. Conditional deletion of Lhx6
results in the developmental loss of Lhx6 neurons in hypothalamus but not telencephalon. In
contrast to cortical and hippocampal interneurons, which primarily form local synaptic
connections, hypothalamic Lhx6 neurons extend long-distance projections. We observed
hypothalamic Lhx6 neurons extending descending projections to multiple regions in the
midbrain, including the ventrolateral periaqueductal gray, the dorsal raphe nucleus, and the
substantia nigra. Ascending projections to the amygdala were also observed. We have also used
RNA-sequencing to comprehensively profile the transcriptome of FACS-isolated both
hypothalamic and telencephalon Lhx6-positive neurons from newborn and juvenile Lhx6-EGFP
mice. We find that both groups co-express many genes previously reported to be selectively
expressed in cortical interneurons, but also express dozens of genes specific to each brain region.
In summary, hypothalamic and telencephalon Lhx6 neurons differ substantially in their
development, connectivity, and gene expression profiles.
Disclosures: K. Liu: None. H. Wang: None. S. Blackshaw: None.
Poster
120. Mechanisms of Neuronal Cell Fate Acquisition
Location: Halls A-C
Time: Sunday, November 16, 2014, 8:00 AM - 12:00 PM
Program#/Poster#: 120.02/A2
Topic: A.02. Neurogenesis and Gliogenesis
Support: R00EY019547
Title: Deep sequencing of the developing mouse retina revealed shifts in cell-intrinsic molecular
programs augmented by alternative splicing
Authors: *R. KANADIA
Univ. of Connecticut, Storrs, CT
Abstract: Understanding the spatiotemporal transitions in gene expression including
alternatively spliced isoforms is crucial in developmental biology as it holds the promise of
informing transition in molecular programs executed by the developing system. Deep sequencing
has the potential to inform these transitions as it can capture the transcriptome with great depth,
which in turn can reflect accurate changes in gene expression. Here we employ the developing
retina as the model developing system and leverage the depth of information obtained via deep
sequencing to inform progression of these programs as the tissue develops. Comparison of
embryonic day (E)16 vs. postnatal day (P)0 revealed that genes under active transcription control
are highly alternatively spliced. We also designed a new pipeline to extract biological meaning
from sorted deep sequence data by using available tools such as DAVID and GeneMANIA to
inform changes in gene networks over time. Specifically, we were able to assign functions to the
changes in gene networks thereby allowing us to infer the order in which specific functions such
as axon guidance, vision perception were executed by the developing retina. In all, we show that
deep sequencing data can be analyzed using our approach to extract biologically relevant
functions from any biological system in flux, be it development or disease.
Disclosures: R. Kanadia: None.

Poster
120. Mechanisms of Neuronal Cell Fate Acquisition
Location: Halls A-C
Time: Sunday, November 16, 2014, 8:00 AM - 12:00 PM
Program#/Poster#: 120.03/A3
Topic: A.02. Neurogenesis and Gliogenesis
Support: P01 NS048120
Title: The molecular mechanisms of cortical interneuron fate determination
Authors: *D. TISCHFIELD
Univ. of Pennsylvania/Chop, Philadelphia, PA
Abstract: The cerebral cortex is comprised of excitatory projection neurons (~80%) and
inhibitory GABAergic interneurons (~20%). Whereas projection neurons are generated in the
cortical ventricular proliferative zone, interneurons are generated in distinct ventral eminences
and subsequently migrate dorsally into the developing cortex. The majority of cortical
interneurons arise from progenitors located in the medial ganglionic eminence (MGE), where the
transcription factor (TF) Nkx2.1 is required for their specification. Within the MGE, the TF
Mash1 is important in regulating aspects of early neurogenesis. Intermediate neurogenesis,
which is marked by abventricular neurogenic divisions predominantly in the subventricular zone,
is at least partially regulated by the TF’s Dlx1/2. Necessary for these TF’s to function are global
changes in chromatin structure. However, the epigenetic factors that regulate the transition from
radial glia to intermediate progenitor and post-mitotic interneuron are relatively unknown. Here,
we describe two SWIM domain-containing proteins, Zswim5 and Zswim6, which are expressed
in the SVZ of the MGE across peak stages of interneurogenesis. Based on homology with a
family of bacterial SWIM-containing SWI2/SNF2 ATPases, Zswim5/6 are predicted to interact
with eukaryotic chromatin-associated SWI2/SNF2 ATPases. We hypothesize that Zswim5/6
interact with chromatin remodeling complexes to specifically regulate SVZ differentiation. To
test this hypothesis, we have obtained a constitutive Zswim5 mutant mouse line and are in the
process of generating Zswim5 and Zswim6 conditional mutants. We are also adapting our
Nkx2.1::mCherry and Lhx6::GFP (expressed in post-mitotic interneuron precursors) dual
reporter mouse embryonic stem cell line to express either Zswim5 and/or Zswim6 shRNA and
overexpression alleles. We anticipate that disruption of SVZ neurogenesis will primarily affect
the generation of parvalbumin (PV)-expressing interneuron subtypes, thereby resulting in distinct
electrophysiological and behavioral deficits in adulthood. Together, these tools will be used to
assess the role of Zswim5/6 in the epigenetic regulation of interneuron output from the MGE.
Disclosures: D. Tischfield: None.
Poster
120. Mechanisms of Neuronal Cell Fate Acquisition
Location: Halls A-C
Time: Sunday, November 16, 2014, 8:00 AM - 12:00 PM
Program#/Poster#: 120.04/A4
Topic: A.02. Neurogenesis and Gliogenesis
Support: Singapore-MIT alliance scholarship
Astar, Genome Institute of Singapore
Astar, Institute of molecular and cell biology
Title: Functional role of microRNA-7 in neural development
Authors: *L. ADUSUMILLI1, N. TISO2, C. TEH3, V. KORZH3, L. BING4
1GENOME INSTITUTE OF SINGAPORE, SINGAPORE, Singapore; 2Dept. of Biol., Univ. of
Padova, Padova, Italy; 3Developmental biology, Inst. of molecular and cell biology, Singapore,
Singapore; 4Stem cell and developmental biology, Genome Inst. of Singapore, Singapore,
Singapore
Abstract: Abstract: In the developing central nervous system (CNS) neurons and glia are
sequentially produced from the ventricular neural progenitor cells. The progenitors restrict their
differentiation potential by developmental stage-specific temporal specification. An important
question in developmental neurobiology is to understand the signaling networks and factors that
control switch from neurogenesis to gliogenesis. Understanding the molecular mechanisms
would give us a partial solution of what goes wrong early in development in neurodegenerative
diseases like Alzeimers and Parkinson. Recently microRNA’s have found their importance in
fine tuning key signaling factors in various developmental events. MicroRNAs are short non-
coding RNAs that selectively repress translation of specific mRNA transcripts. These post-
transcriptional regulators orchestrate various important cellular events including self renewal,
differentiation and cell type specification. We characterized miRNA expression changes during
the differentiation of human neuroblastoma cell line SH-SY5Y through miRNA profiling.
microRNA-7 was highly upregulated during neuronal differentiation in vitro, suggesting an
analogous potential role for miR-7 during neural development in vivo. Ectopic expression of this
microRNA in both human neural cell lines and zebrafish resulted in a more glial cell phenotype
particularly giving rise to more number of oligodendrocytes and less neurons. Loss of function
resulted in an increase in the production of mature neurons specifically dopaminergic neurons in
the ventral part of the forebrain region. To identify potential target genes regulated by miR-7, we
profiled the global changes in gene expression following miR-7 ectopic expression in ReNVM
and neural progenitor cells derived from human ES cells. miR-7 represses around 143 targets
that contain the seed match sequence of the microRNA and are predicted targets of miR-7 by
conventional methods. The key targets repressed by microRNA-7 were TCF/LEF family
members which act as downstream effectors of canonical Wnt/β-catenin signaling pathway.
Using transgenic Wnt TCF reporter lines in zebrafish we have shown this microRNA negatively
regulates the Wnt signaling pathway in-vivo. Ectopic expression of miR-7 resulted in early
induction of the sonic hedgehog pathway which is antagonistic to Wnt pathway. Together, we
report for the first time the role of a microRNA in maintaining a pool of progenitor cells by
negatively regulating the canonical Wnt-β catenin pathway and controlling the timing and
production of both the glial and neuronal subtypes in the central nervous system.
Disclosures: L. Adusumilli: None. N. Tiso: None. C. Teh: None. V. Korzh: None. L. Bing:
None.

Poster
120. Mechanisms of Neuronal Cell Fate Acquisition
Location: Halls A-C
Time: Sunday, November 16, 2014, 8:00 AM - 12:00 PM
Program#/Poster#: 120.05/A5
Topic: A.02. Neurogenesis and Gliogenesis
Support: CONICYT
FONDECYT-1120483
INICIATIVA CIENTIFICA MILENIO ICM-P09-015-F
Title: The specification of cortical subcerebral projection neurons depends on the direct
repression of TBR1 by CTIP1
Authors: J. CÁNOVAS1, A. BERNDT1, H. SEPÚLVEDA2, R. AGUILAR2, F. A. VELOSO2,
M. MONTECINO2, C. OLIVA1, J. C. MAASS1, J. SIERRALTA1, *M. KUKULJAN1
1Biomed. Neurosci. Inst. and Program in Physiol. and Biophysics, Univ. de Chile, Santiago,
Chile; 2Ctr. for Biomed. Res. and FONDAP Ctr. for Genome Regulation, Univ. Andrés Bello,
Santiago, Chile
Abstract: The six-layered neocortex comprises hundreds of projection neuron (PN) subtypes
that are generated in a tightly orchestrated sequence from pallial progenitors. PNs residing at
distinct laminar positions acquire specific fates defined in terms of gene expression profiles,
morphological and functional features and connectivity patterns. PNs are categorized into
corticofugal PNs, which reside in deep layers (layers 5 and 6) and intracortical PNs which send
their axons to the ipsilateral or contralateral cortex and are found within superficial cortical
layers (2/3), as well as in layer 5. The specification of cortical PN subtypes is regulated by a
complex network of transcriptional interactions in which FEZF2, SATB2, CTIP2 and TBR1
appear to have central roles in the choice between the intracortical versus corticofugal fates. To
further understand how the diversity of PN is established we studied the role of the transcription
factor CTIP1, which is expressed during mouse developing cerebral cortex and acquires a
laminar expression pattern in the post-natal neocortex showing high expression levels in layers
2/3 and 5 and low expression levels in layer 6. We observed a reciprocal expression pattern
between CTIP1 and TBR1 in deep cortical layers. We found that CTIP1 functions as a repressor
of the Tbr1 gene expression. In vivo decrease of CTIP1 expression by in utero electroporation of
shRNAs in layer 5 PN led a to an increase in TBR1, associated to a decrease of CTIP2 and the
loss of subcerebral projecting axons (SCPA); the defect of SCPA is mediated by TBR1
derepression. Since a marked difference in CTIP1 expression between layer 5 and 6 neurons
exists, we propose that these different levels of CTIP1 expression lead to differential degrees of
repression of the Tbr1 gene and thus contribute to establish the alternative fates of PN in deep
cortical layers.
Disclosures: J. Cánovas: None. R. Aguilar: None. F.A. Veloso: None. M. Montecino:
None. H. Sepúlveda: None. M. Kukuljan: None. A. Berndt: None. C. Oliva: None. J.C.
Maass: None. J. Sierralta: None.

Poster
120. Mechanisms of Neuronal Cell Fate Acquisition
Location: Halls A-C
Time: Sunday, November 16, 2014, 8:00 AM - 12:00 PM
Program#/Poster#: 120.06/A6
Topic: A.02. Neurogenesis and Gliogenesis
Support: NIH Grant T32 GM 063483
Title: The zinc finger transcription factor Tshz1 is necessary for development of the intercalated
cells of the amygdala
Authors: *J. KUERBITZ1, S. EHRMAN1, A. N. GARRATT2,3, R. R. WACLAW4, K.
CAMPBELL1
1Developmental Biol., Cincinnati Children's Hosp., Cincinnati, OH; 2Neurosci. Program, Max-
Delbrück-Center for Mol. Med. (MDC), Berlin, Germany; 3Inst. of Cell Biol. and Neurobiology,
Ctr. for Anat., Charité Univ. Hosp., Berline, Germany; 4Exptl. Hematology and Cancer Biol.,
Cincinnati Children's Hosp. Med. Ctr., Cincinnati, OH
Abstract: The intercalated cell (ITC) groups of the amygdala are clusters of GABAergic
interneurons that surround the basolateral complex of the amygdala and have been shown to act
to modulate amygdalar control of anxiety responses. Previous studies have demonstrated that
ITCs originate in the embryonic dorsal lateral ganglionic eminence (dLGE) at embryonic time
points. The zinc finger transcription factor Tshz1 is expressed in a subpopulation of cells in the
embryonic dLGE and in mature ITCs . However, the importance of Tshz1 expression for ITC
development remains unknown. We have utilized germline Tshz1GFP knock-in/knock-out mice to
follow the normal development of ITCs as well as to investigate whether Tshz1 expression is
necessary for proper development of ITCs. Mature Tshz1GFP positive cells co-express the
transcription factors FoxP2 and Meis2. Moreover, E18.5 E 18.5 Tshz1GFP expressing Tshz1
knockout mice (Tshz1GFP/RA) show an ectopic cluster of GFP positive cells at the dorsal, medial
border of the Lateral Amygdala (LA) and a severe reduction of ventral and rostral GFP positive
ITC cells on the lateral side of the basolateral complex and in the IA. These findings suggest that
ITCs can be generated in the absence of Tshz1 but their migration and settling patterns in the
amygdala require are dependent on its function. Furthermore, many of these clumped cells ITCs
in the mutant amygdala ectopically express the dLGE transcription factors Sp8 and Pax6
suggesting that Tshz1 is required to down-regulate these factors as they migrate towards the
amygdala. We are currently attempting to determine whether the ectopic expression of these
factors contributes to the observed migration defects. Finally, our preliminary studies on
forebrain- specific conditional deletion of Tshz1 mediated by FoxG1tTA and tetO-Cre results in a
substantial loss of ITCs at postnatal time points. Our data suggest that Tshz1 may play an
important role in regulating migration and gene expression in developing ITCs. Future studies,
will determine the effect of this phenotype on fear and anxiety behaviors.
Disclosures: J. Kuerbitz: None. K. Campbell: None. S. Ehrman: None. R.R. Waclaw:
None. A.N. Garratt: None.

Poster
120. Mechanisms of Neuronal Cell Fate Acquisition
Location: Halls A-C
Time: Sunday, November 16, 2014, 8:00 AM - 12:00 PM
Program#/Poster#: 120.07/A7
Topic: A.02. Neurogenesis and Gliogenesis
Title: Splice variants differentially regulate gene regulatory networks required for neural
differentiation of GABAergic motor neurons in Caenorhabditis elegans
Authors: *R. CAMPBELL, W. W. WALTHALL
Georgia State Univ., Atlanta, GA
Abstract: Differentiation of the nervous system is a multi-level process in which multiple gene
networks coordinate to specify post mitotic differentiation in neurons. How these networks are
coordinated is an area of intense interest. Using Caenorhabditis elegans as a model, the
coordination of such networks can be investigated by examining the regulation of transcription
factors required for post mitotic neuronal differentiation. The GABAergic motor neurons of C.
elegans represent an excellent model to study differentiation of neuronal subtypes. These
GABAergic motor neurons can be divided into two classes: the DD motor neurons are
responsible for innervation of dorsal muscle, whereas the VD motor neurons are responsible for
innervation of ventral muscle. The coordinated cross-inhibitory action of the VD and DD motor
neurons in conjunction with the excitatory cholinergic motor neurons allows the animal to move
in a sinuous pattern. The VD motor neurons are distinguished from the DD motor neurons by the
expression of the COUP-TFII homolog, UNC-55. This study focuses on the transcriptional
regulation of an unc-55::gfp reporter, which is expressed in the VD motor neurons. Utilizing
bioinformatics, putative transcription factor binding sites (cis sites) were found on the unc-55
promoter. Several putative cis site corresponds with the MEIS domain transcription factor, UNC-
62. Different mutant alleles of UNC-62 repress and activate UNC-55::GFP expression. There are
10 predicted splice variants of unc-62 and mutations have been identified in specific exons some
of which are alternatively spliced. We are investigating the possibility that different mutated
isoforms activate or repress the unc-55 reporter. Dissection of the unc-55 promoter identified
multiple regions that correlate with the UNC-62 mutant expression patterns. This provides
additional evidence for isoform specific regulation of UNC-55. Isoform specific transcriptional
regulation of differentiating neurons is a relatively unexplored area of research. Further work in
this new area of development would further the field of neuroscience and development.
Disclosures: R. Campbell: None. W.W. Walthall: None.

Poster
120. Mechanisms of Neuronal Cell Fate Acquisition
Location: Halls A-C
Time: Sunday, November 16, 2014, 8:00 AM - 12:00 PM
Program#/Poster#: 120.08/A8
Topic: A.02. Neurogenesis and Gliogenesis
Support: NIH grant DC008955
Burke Medical Research Institute
Title: Novel molecular mechanism in regulatingtyrosine hydroxylase transcription
Authors: *M. WANG1, K. BANERJEE1, E. CAI1, N. FUJIWARA1, H. BAKER1,2, J. W.
CAVE1,2
1Burke Med. Res. Inst., White Plains, NY; 2Brain and Mind Res. Inst., Weill Cornell Med. Col.,
New York, NY
Abstract: Specification and maintenance of the dopaminergic neuronal phenotype requires tight
regulation of Tyrosine hydroxylase (Th) transcription, but the molecular mechanisms regulating
Th expression are not fully understood. In this study, we define a novel transcription regulatory
mechanism mediated by two previously unreported and highly conserved G:C-rich regions in the
Th proximal promoter. These regions are targeted by heterogeneous nuclear ribonucleoprotein
(hnRNP) K, which preferentially binds C-rich single stranded DNA within these conserved
regions. hnRNP K can also associate with the double stranded DNA sequences of the G:C-rich
regions, but this interaction requires bZIP DNA binding domain proteins, such as CREB, bound
to an adjacent cis-regulatory element. Both in vitro and in vivo studies also reveal that the single
DNA strands within both conserved G:C-rich regions adopt either G-quadruplex or i-motif
secondary structures that repress Th promoter activity. We describe studies to test whether
inhibition of Topoisomerase I by topotecan indirectly stabilizes these structures on the Th
promoter. We also show that direct interactions with small molecules stabilize these DNA
secondary structures, suggesting that these structures are novel targets for pharmacological
modulation of the dopaminergic phenotype. Together, these findings establish a novel molecular
regulatory mechanism for Th transcription that appears to be conserved in vertebrates.
Disclosures: M. Wang: None. K. Banerjee: None. E. Cai: None. N. Fujiwara: None. H.
Baker: None. J.W. Cave: None.

Poster
120. Mechanisms of Neuronal Cell Fate Acquisition
Location: Halls A-C