The E3 ligase ube3a is required for learning in Drosophila melanogaster
Q6
Q5
Moumita Chakraborty
1
, Blesson K. Paul
1
, Tanmoyita Nayak
2
, Aniruddha Das
3
,
Nihar R. Jana, Supriya Bhutani
*
Department of Cellular and Molecular Neurosciences, National Brain Research Centre, NH8, Nainwal Mode, Manesar, Haryana,122051, India Q1
article info
Article history:
Received 3 April 2015
Available online xxx
Keywords:
Angelman syndrome
Autism
E6-AP
Learning
ube3a
abstract
Angelman syndrome and autism are neurodevelopmental disorders linked to mutations and duplications
of an E3 ligase called ube3a respectively. Since cognitive deficits and learning disabilities are hallmark
symptoms of both these disorders, we investigated a role for dube3a in the learning ability of flies using
the aversive phototaxis suppression assay. We show that down and up-regulation of dube3a are both
detrimental to learning in larvae and adults. Using conditional gene expression we found that dube3a is
required for normal brain development and during adulthood. Furthermore, we suggest that dube3a
could be interacting with other learning and memory genes such as derailed. Along with firmly estab-
lishing dube3a as a gene that is required for learning, our work also opens avenues for further under-
standing the role played by this gene in brain development and behavior.
© 2015 Published by Elsevier Inc.
1. Introduction
Angelman syndrome (AS) is a neurodevelopmental disorder
that is characterized by severe intellectual disability, develop-
mental delay, jerky limbs, frequent seizures and uncontrollable
laughter [1]. Autism, another neurodevelopmental disorder, con-
stitutes a broad spectrum of disorders which are commonly asso-
ciated with diminished social interactions, impaired
communication and increased repetitive behaviors [2]. Interest-
ingly, both these disorders are strongly associated with genetic
abnormalities at the q11-13 locus of human chromosome 15 [3e5].
In particular, a gene called ube3a is present at this site which, when
mutated, seems to be sufficient to manifest AS, and when dupli-
cated is linked to autism. ube3a is known to be imprinted in neu-
rons with the maternal allele expressed and the paternal one
silenced [6]. Deletion or mutations of maternal ube3a result in its
complete loss in neurons and cause AS [7,8]. In contrast, duplication
of the maternal allele results in excess ube3a in the brain and may
be linked to autism spectrum disorders [9]. The ube3a protein is an
E3 ligase which attaches ubiquitin to its target substrates and tags
them for degradation. It has also been reported that ube3a acts as a
transcriptional co-activator of steroid hormone receptors [10].
Transgenic mice with maternally deficient ube3a are defective in
context-dependent learning and long term potentiation with
numerous signaling pathways implicated [11e 14]. Fly models of AS
in which the Drosophila homolog of ube3a (dube3a) is deleted
recapitulate disease symptoms such as defects in locomotion,
circadian rhythms and memory [15]. Mutant flies also have
impaired dendritic branching, a phenotype that was later observed
in pyramidal neurons of mice [16,17].
Since cognitive deficits and learning disabilities are common to
patients of both AS and autism, we performed a detailed investi-
gation into the effect of altered levels of dube3a on the learning
ability of flies and demonstrate its spatial and temporal require-
ment for this behavior. Furthermore, we demonstrate a potential
genetic interaction between dube3a and derailed, a receptor tyro-
sine kinase linked to learning and memory.
2. Materials and methods
2.1. Fly stocks and culture
Fly stocks were maintained at 25 ± 1
C in BOD incubators
(LD12:12) on standard sugar yeast food. Stocks e dube3a
PE
,
* Corresponding author.
E-mail addresses: moumita.biochem89@gmail.com (M. Chakraborty),
blessonmustard@gmail.com (B.K. Paul), titirnk@gmail.com (T. Nayak),
aniruddhadas86@gmail.com (A. Das), nihar@nbrc.ac.in (N.R. Jana), supriya@nbrc.
ac.in, bhutanisupriya@yahoo.co.uk (S. Bhutani).
1
Equal contribution. Q2
2
Current address: Unit of Molecular Cell Biology, Johannes Gutenberg University,
Bentzelweg 3, Mainz, 55128, Germany.
3
Current address: Sagol Dept. of Neurobiology, University of Haifa, Haifa,
3498838, Israel.
Contents lists available at ScienceDirect
Biochemical and Biophysical Research Communications
journal homepage: www.elsevier.com/locate/ybbrc
http://dx.doi.org/10.1016/j.bbrc.2015.04.110
0006-291X/© 2015 Published by Elsevier Inc.
Biochemical and Biophysical Research Communications xxx (2015) 1e7
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YBBRC33856_proof ■ 1 May 2015 ■ 1/7
Please cite this article in press as: M. Chakraborty, et al., The E3 ligase ube3a is required for learning in Drosophila melanogaster, Biochemical and
Biophysical Research Communications (2015), http://dx.doi.org/10.1016/j.bbrc.2015.04.110