The Journal of Neuroscience, November 26, 2008, 28(48):12748-12758; doi:10.1523/JNEUROSCI.4349-08.2008
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Development/Plasticity/Repair
Serotonergic Transcription of Human FEV Reveals Direct GATA Factor Interactions and Fate of Pet-1-Deficient Serotonin Neuron Precursors
Katherine C. Krueger and
Evan S. Deneris
Department of Neurosciences, Case Western Reserve University, School of Medicine, Cleveland, Ohio 44106
Correspondence should be addressed to Evan Deneris, Case Western Reserve University, School of Medicine, Department of Neuroscience, 2109 Adelbert Road, Cleveland, OH 44106-4975. Email: esd{at}case.edu
Altered expression of the human FEV (fifth Ewing variant) ETS transcription factor gene impacts the level of CNS serotonin (5-HT) neuron gene expression and maternal nurturing. However, the regulatory mechanisms that determine FEV expression are poorly understood. Here, we investigated the cis-regulatory control of FEV to begin to identify the upstream transcription factors that restrict FEV expression to 5-HT neurons. We find that sequences extending only 275 bp upstream of the FEV 5' untranslated region are sufficient to direct FEV transgene expression to embryonic 5-HT neurons, although sequences farther upstream are required for maintenance in adult 5-HT neurons. Two highly conserved consensus GATA factor binding sites within the 275 bp region interact with GATA factors in vitro. Chromatin immunoprecipitations with embryonic hindbrain demonstrated Gata-2 interactions with the orthologous mouse Pet-1 ETS cis-regulatory region. Mutagenesis of GATA sites revealed that one or the other site is required for serotonergic FEV transgene expression. Unexpectedly, FEV–LacZ transgenes enabled determination of 5-HT neuron precursor fate in the adult Pet-1–/– dorsal and median raphe nuclei and thus provided additional insight into FEV/Pet-1 function. Comparable numbers of FEV–LacZ-positive cells were detected in Pet-1+/– and Pet-1–/– adult dorsal raphe nuclei, indicating that the majority of mutant serotonergic precursors are not fated to apoptosis. However, B7 dorsal raphe cells were aberrantly distributed, suggesting a role for FEV/Pet-1 in their midline organization. Our findings identify a direct transcriptional interaction between Gata-2 and FEV and a unique marker for new insight into FEV/Pet-1 function in 5-HT neuron development.
Key words: FEV; Pet-1; GATA-2; serotonin; cis-regulatory; transgenic
Received Sept. 11, 2008;
accepted Oct. 8, 2008.
Correspondence should be addressed to Evan Deneris, Case Western Reserve University, School of Medicine, Department of Neuroscience, 2109 Adelbert Road, Cleveland, OH 44106-4975. Email: esd{at}case.edu