Gene Mutations Involved in Brain Development and Autism Spectrum Disorders

Expression Staining to Qualify Presence of Dscam Expression

Gene Mutations Involved in Brain Development and Autism Spectrum Disorders

By: Alexandra Flores    Email:  flor3662@vandals.uidaho.edu

Home Town: Caldwell, ID    High School: Thomas Jefferson Charter School

Major: Biochemistry
Department: Biological Sciences
College: College of Science

Hippocampus stained with hematoxylin and eosin to count cells

Autism Spectrum
Disorder (ASD) is a developmental disability characterized by sensory and
communication deficits. Recently, diagnosis of ASD has increased, and it is now
estimated to affect 1 in 68 children. The symptoms of autism begin to appear
during the first three years of life, which coincides with the development of
learning ability and a critical period of synaptogenesis. Because synaptic
changes are thought to be the basis of all learning, mutations that may affect
the neural synapse have been shown to cause the mental retardation phenotype
that is associated with autism. Research into the specifics of these synaptic
mutations has given evidence that synaptic cell adhesion proteins contribute to
autism with at least 28 of the 200 genes associated with autism being
identified as cell adhesion molecules (CAMs) or CAM-related.

One CAM with expression
mutations that have been associated with ASD is Down Syndrome Cell Adhesion
Molecule (DSCAM), which functions in neural development, including axon
guidance, axonal and dendritic branching and targeting, and synapse maturation.
DSCAM has been extensively studied in mice where mutations in the gene have
been found to impair aborization, the processes and spacing of a neuron’s
dendrites, cell death, axon pathfinding, and synaptic pairing between different
types of neurons. However, almost all of these studies have been done only in
the retina. Dscam is also expressed
in the cerebral cortex, dentate gyrus, thalamus, cerebellum, olfactory bulb,
and hippocampal neurons in mice. An analysis of the structure in these major
brain regions of Dscam mutant mice
can allow for a comparison between the brains of these mice and the brains of
people with Dscam expression
disorders in order to determine if mice will make a good model to test clinical
interventions for ASD treatment. Preliminary results have shown gross defects
in Dscam mutant mouse brains, and we
aim to analyze the brain regions that are affected in order to better
understand DSCAM’s impact on brain function and development.

Genetically-modified
mice with loss of function and gain of function phenotypes will be examined to
gain a better understanding of DSCAM’s effect on bran function and development.
Mouse brains will be analyzed using hematoxylin and eosin staining to identify
major brain regions and count cell populations within those regions. The populations
will be analyzed according to their organization by comparing cell density.
Initial studies will place emphasis on the cerebellum, hippocampus, midbrain,
cerebral cortex, and motor cortex. We will also be working closely with
computer scientists to generate a digital reconstruction of the major brain
regions in order to create a searchable template similar to The Allen Brain
Atlas, an online resource that documents different regions of the wild type
mouse brain, where the impact of Dscam
mutations can be observed.

 


Products Produced:

Type: Title: Date Published/Presented: DOI:
Poster Characterizing Differences in the Superior Colliculus of Genetic Mouse Models for Autism March 20, 2019
Poster Genetic Mutations Involved in Brain Development and Autism Spectrum Disorders July 31, 2019
Presentation Genetic Mutations Involved in Brain Development and Autism Spectrum Disorders July 31, 2019
Presentation Genetic Mutation in the Brain that Contributes to Autism August 3, 2018

Additional Project Information:

Year in College Project Started:  Sophomore

Faculty Advisor:   Peter  Fuerst

Faculty Advisor Email:   fuerst@uidaho.edu

Faculty Advisor Website:  

Funding Source:  Arnold and Mabel Beckman Foundation

External Link to Project Information:  

Project Location:   Moscow, ID