Motifs and cis-regulatory modules mediating the expression of genes co-expressed in presynaptic neurons.
BACKGROUND
Hundreds of proteins modulate neurotransmitter release and synaptic plasticity during neuronal development and in response to synaptic activity. The expression of genes in the pre- and post-synaptic neurons is under stringent spatio-temporal control, but the mechanism underlying the neuronal expression of these genes remains largely unknown.


RESULTS
Using unbiased in vivo and in vitro screens, we characterized the cis elements regulating the Rab3A gene, which is expressed abundantly in presynaptic neurons. A set of identified regulatory elements of the Rab3A gene corresponded to the defined Rab3A multi-species conserved elements. In order to identify clusters of enriched transcription factor binding sites, for example, cis-regulatory modules, we analyzed intergenic multi-species conserved elements in the vicinity of nine presynaptic genes, including Rab3A, that are highly and specifically expressed in brain regions. Sixteen transcription factor binding motifs were over-represented in these multi-species conserved elements. Based on a combined occurrence for these enriched motifs, multi-species conserved elements in the vicinity of 107 previously identified presynaptic genes were scored and ranked. We then experimentally validated the scoring strategy by showing that 12 of 16 (75%) high-scoring multi-species conserved elements functioned as neuronal enhancers in a cell-based assay.


CONCLUSIONS
This work introduces an integrative strategy of comparative genomics, experimental, and computational approaches to reveal aspects of a regulatory network controlling neuronal-specific expression of genes in presynaptic neurons.
Liu
Rui
R
Department of Genetics and Penn Center for Bioinformatics, University of Pennsylvania, Philadelphia, PA 19104, USA.
Hannenhalli
Sridhar
S
Bucan
Maja
M
D000465:Algorithms; D000818:Animals; D001665:Binding Sites; D001921:Brain / Q000166:cytology / Q000254:growth & development / Q000378:metabolism*; D002460:Cell Line; D045744:Cell Line, Tumor; D005260:Female; D020869:Gene Expression Profiling; D018507:Gene Expression Regulation, Developmental; D049452:Green Fluorescent Proteins / Q000235:genetics / Q000378:metabolism; D006367:HeLa Cells; D006801:Humans; D007150:Immunohistochemistry; D008156:Luciferases / Q000235:genetics / Q000378:metabolism; D008297:Male; D051379:Mice; D008822:Mice, Transgenic; D009474:Neurons / Q000166:cytology / Q000378:metabolism*; D020411:Oligonucleotide Array Sequence Analysis; D017729:Presynaptic Terminals / Q000378:metabolism*; D012045:Regulatory Sequences, Nucleic Acid; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014157:Transcription Factors / Q000378:metabolism; D014162:Transfection; D020826:rab3A GTP-Binding Protein / Q000235:genetics / Q000378:metabolism
D014157:Transcription Factors; D049452:Green Fluorescent Proteins; D008156:Luciferases; D020826:rab3A GTP-Binding Protein