Biology Reference
In-Depth Information
Table 11.3: Some Single Genes Involved in Learning and Memory of
Drosophila melanogaster.
Gene
Mutant phenotype(s)
Function(s)
dunce
+
Short-term memory defective
cAMP-specific phosphodiesterase involved in olfactory
learning and memory
Affects locomotor rhythms, ethanol tolerance, learning
rutabaga
+
Short-term memory defective
Adenylate cyclase decreases expression of cAMP, affects
courtship, learning, ethanol tolerance, grooming
amnesiac
+
Middle-term memory defective
Neuropeptide, stimulates cAMP synthesis
Affects ethanol tolerance, sleep regulation
radish
+
Anesthesia-resistant long-term memory
Affects only one type of long-term memory
cabbage
+
Long- and short-term memory (?)
Involved in olfactory learning
turnip
+
Long- and short-term memory
Involved in the protein kinase C pathway
Affects olfactory discrimination, larval, visual and
reward learning
latheo
+
Acquisition of initial memory defective?
Involved in short-term memory; affects DNS
replication and synaptic plasticity?
linotte
+
Retarded learning
Mutants have structural brain defects
(mushroom bodies and central complex)
Encodes receptor tyrosine kinase
Volado
+
Short-term memory
Expressed in mushroom bodies
Cell surface receptor altered, involved in synaptic
remodeling underlying learning and memory; two
variants of
α
-integrin coded for
leonardo
+
Short-term and olfactory learning
Affects protein 14-3-3-, which is involved in
intracellular signaling that activates and represses
protein kinase C activity, activates tyrosine
hydroxylase and tryptophan hydroxylase (enzymes
involved in catecholamine and serotonin synthesis)
(Adapted from
Dubnau and Tully 1998, Sokolowski 2001, Waddell and Quinn 2001
, FlyBase.)
cells that help form associative memories. The
dunce
flies have impaired synap-
tic transmission because the excess of cAMP leads to hyperpolarization of the
synaptic terminals, resulting in a chronically lowered availability of neurotrans-
mitter (
Delgado et al. 1992
).
The
dunce
+
gene is one of the largest and most complex identified in
Drosophila
, extending over 140 kb. It produces, by the use of multiple transcrip-
tion start sites and alternative splicing of exons and differential processing of 3
′
sequences, at least eight to ten RNAs ranging from 4.2 to 9.5 kb. One unusually
large intron, 79 kb in length, contains at least two genes (
Sgs-4
and
Pig-1
) within
it (
Chen et al. 1987, Qiu et al. 1991
). This “genes-within-an-intron” arrange-
ment is uncommon. One of the contained genes,
Sgs-4
+
, is expressed in larval
salivary glands and provides the glue used by larvae to attach themselves to the
