The Journal of Neuroscience, July 1, 2002, 22(13):5291-5299
Abnormal Chemosensory Jump 6 Is a Positive Transcriptional
Regulator of the Cholinergic Gene Locus in Drosophila
Olfactory Neurons
Mi-Heon
Lee and
Paul M.
Salvaterra
Division of Neuroscience, Beckman Research Institute of the City of
Hope, Duarte, California 91010
Cholinergic neurons acquire their neurotransmitter phenotype, in
part, by expressing the cholinergic gene locus. Previous studies have
indicated that the 5' flanking DNA of the locus contains both positive
and negative regulatory elements important for expression in different
subsets of cholinergic neurons in Drosophila and other
animals. Approximately 300 bases of proximal 5' flanking DNA control
expression in Drosophila CNS neurons essential for viability, whereas more distal regulatory elements are important for
expression in PNS sensory neurons. In this study we identify the POU
domain transcription factor abnormal chemosensory jump 6 (Acj6)
as a necessary positive transcriptional regulator for cholinergic locus
expression in primary olfactory neurons. Choline acetyltransferase
enzyme activity, protein levels, mRNA, and a fluorescent cholinergic
reporter gene are all decreased in olfactory neurons of
acj6 mutants. Decreased cholinergic expression was observed in both adults and larvae. The presence of a specific Acj6
binding site has been identified in the cholinergic locus 5' flanking
DNA, suggesting that Acj6 may play a direct role in specifying the
cholinergic neurotransmitter phenotype of most olfactory neurons.
Transgenic expression of two different isoforms of Acj6 restricted to
olfactory neurons indicates that additional trans
factors may be required for cholinergic locus expression. Transgenic
expression in all cholinergic neurons, however, results in lethality
when a POU IV box element is absent but is essentially benign when
present, indicating the importance of this motif in specifying
different functional roles for Acj6.
Key words:
cholinergic locus; POU domain transcription factor; POU
IV box; Acj6; neurotransmitter phenotype; olfactory neurons
Copyright © 2002 Society for Neuroscience 0270-6474/02/22135291-09$05.00/0