Page 70 - Mouse Molecular Genetics

Full Abstracts
Program number is above title. Author in bold is the presenter.
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a marker for heart failure, at the mRNA level than non-pregnant HcB-23 ( p0.001). The findings suggest that the impaired
reproductive performance in HcB-8 mice reflects failure of maternal vascular adaptations to pregnancy. Preliminary data in
congenic mice in which the QTL has been isolated are consistent with those obtained in HcB-8 and HcB-23.
103
A mouse model of human Branchio-Oculo-Facial Syndrome. Hong Li
,
Trevor Williams. Department of Craniofacial Biology,
University of Colorado Denver AMC, Aurora, CO.
Human Branchio-Oculo-Facial syndrome (BOFS) is a dominantly inherited birth defect, which has a range of craniofacial
malformations including skull deformity, cleft lip, abnormal external ear morphology, malformed nasal tip, nasolacrimal duct
obstruction, and small teeth. Associated problems are eye defects, hearing deficits, branchial clefts and melanocyte dysfunction.
The phenotypes show variability. Recent data have indicated that this condition is caused by missense mutations in AP-
2 (
TFAP2A) that alter conserved amino acid residues, particularly within the DNA binding domain. One of the outstanding
questions about human BOFS is whether the condition is caused by haploinsufficiency of AP-2, or if the mutant proteins have a
dominant negative effect on the remaining wild-type allele. We have generated mouse models to distinguish between these
possibilities. Mice carrying an AP-2 BOFS allele in association with a wild-type allele show more severe defects than mice
lacking one copy of AP-2. These findings indicate that the BOFS alleles are working in a dominant negative manner, and the
syndrome is not caused by simple haploinsufficiency. Phenotypes in the BOFS mice have many overlaps with those seen in
affected humans, including facial clefting and defects in skin, eye, and ear morphology. The mouse model shows variable
expressivity, similar to the variability seen in humans. Other phenotypes we observe, including neural tube and limb defects, may
help inform the analysis of the affected human population. The phenotype of BOFS homozygous mice indicates that the
mutations are acting more broadly than on AP-2 alone - possibly affecting the function of other AP-2 gene family members or
co-activators. In conclusion, we have developed a mouse model of human BOFS. This model can be used to probe embryonic
development and underling molecular mechanisms of BOFS.
104
Heterogeneous behavioral manifestations in a mouse model of fetal alcohol spectrum disorders (FASD): Assessing the
effect of gestational time and gene expression. Katarzyna Mantha
,
Morgan Kleiber, Benjamin Laufer, Shiva Singh. Western
University, London, Canada.
Considerable attention has been given to the effect of prenatal alcohol abuse, resulting in well-known cognitive and behavioral
deficits termed fetal alcohol spectrum disorders (FASD). Measures to prevent this disorder have been ineffective, primarily due
to poor understanding. Towards an explanation of its complexity, we have used an animal model and numerous exposure
paradigms to assess its impact on the heterogeneity of behavioral manifestations. The results are assessed in the context of
underlying changes in the transcriptome. We have modeled acute alcohol exposure using ethanol injections in C57BL/6J mice on
gestational days (G) 8 and 11 (trimester 1), G14 and 16 (trimester 2) and postnatal days (P) 4 and 7 (trimester 3). The resulting
offspring are followed from birth until early adulthood using a battery of behavior tests. At maturity (P70), mice are sacrificed
and whole brains are used for genome-wide expression analysis and assessment of epigenetic features using microarrays. The
nature of genes affected by ethanol is considered using bioinformatic tools. Results of this study show that behavioral
heterogeneity of FASD can be partly explained by timing of exposure. Ethanol treatment, independent of trimester, led to motor
skill delays and spatial learning deficits (
p
0.05).
Treatment in trimesters 1 and 2 increased activity levels in juveniles (trimester 1,
ethanol=2835.6136.8, control=2332.1142.9 beam breaks; trimester 2, ethanol=3429.193.8, control=2291.598.6 beam breaks).
Thigmotaxis was increased (
p
0.01)
for trimester 3 ethanol mice (51.46.1 sec in centre) compared to controls (78.16.9 sec in
centre). Analysis of the transcriptomes results in relevant pathways such as interleukin and cell signaling networks. We have
validated many of the genes including
Tnfrsf19
(
p
=0.02) in trimester 1,
Cdkn1a
(
p
=0.02) in trimester 2 and
Cnr1
(
p
=0.004) in
trimester 3. Our results argue that such effects are brought about by epigenetic changes that downregulate a set of imprinted non-
coding RNAs. The genes affected explain most of the phenotypic consequences. These results represent a comprehensive
comparison of behaviors representing a range of behavioral alterations in a mouse model of FASD. Further, FASD-related
abnormalities are correlated with brain gene expression changes. We conclude that common epigenetic modifications play a
critical role in regulating developmental pathways in specific brain regions, contributing to FASD.
105
Secreted protein coding” genes identified by mining the NOD mouse pancreatic lymph node (PLN) transcriptome,
before any clinically detectable pancreatic damages. Evie Melanitou
1
,
Fredj Tekaia
2
,
Edouard Yeramian
3
. 1)
Immunophysiology & Parasitism laboratory, Department of Parasitology and Mycology; 2) Yeast Molecular Genetics Unit,
Department of Genomics & Genetics; 3) Structural Bioinformatics Unit, Department of Structural Biology & Chemistry, Institut
Pasteur, Paris, France.
Statement of purpose:
Our aim is to delineate and characterize the early clinically silent mechanisms operating at the onset of
the auto-reactive processes resulting in overt Type 1 Diabetes (T1D). This could serve two purposes: i) identify early diagnostic
markers and ii) generate data sets to refine the impact of the environment (in particular of hosting microbes) in either NOD
mouse sterile tissues or in microbiota-containing tissues.
Methods used:
We used microarray analysis of the PLN of NOD mice
(
GEO series accession number GSE15582), selected for an early T1D subphenotype (E-Insulin AutoAntibodies) (Melanitou
et al
,
2004;
Regnault
et al
, 2009).
Novel data mining is presented according to in silico analyses with online tools for functional,