Date of Award
2010
Document Type
Honors Thesis (Colby Access Only)
Department
Colby College. Biology Dept.
Advisor(s)
Joshua Kavaler
Second Advisor
Tariq Ahmad
Third Advisor
Russell Johnson
Abstract
Sensory organ differentiation is a complex process known to be developmentally regulated by transcription factor networks. One such factor is D-Pax2, known to be necessary for proper bristle differentiation in Drosophila melanogaster. The expression pattern of D-Pax2 reveals that it is regulated spatially and temporally, yet how such precise regulation is done is unknown. To determine how D-Pax2 is regulated we created multiple sets of reporter constructs bearing pieces of the presumptive bristle specific enhancer of D-Pax2 coupled to GFP. We proposed that proneural genes of the achaete-scute complex, known to be necessary for sensory organ specification, were regulating D-Pax2 through four E-box sites that were found at most 1.6 kb from the transcription start site. Reporter constructs bearing the enhancer with E-box sites mutated did not show reporter gene expression suggesting the necessity of these sites in normal D-Pax2 activation. Further experiments in which ectopic expression of the proneural gene scute caused reporter gene expression to follow support our hypothesis that proneural genes act upstream of D-Pax2. By cloning D-Pax2 enhancer fragments of varying size, we were also able to determine that later D-Pax2 expression is controlled by an unknown element lying between 2 and 3kb upstream of the transcription start site. This element appears to be controlled independently of the early proneural enhancer and in an autoregulatory manner where D-Pax2 either directly or indirectly activates its own transcription. Our evidence thus indicates that D-Pax2 is controlled temporally through two separate enhancers; the proximal proneural enhancer controlling early expression and the distal autoregulatory enhancer controlling later expression
Keywords
D-Pax2, Drosophila, Bristle Differentiation, scute, E-box, Proneural Genes
Recommended Citation
Johnson, Seth A., "External Sensory Organ Expression of D-Pax2 is Activated by Two Temporally Distinct Enhancers" (2010). Honors Theses. Paper 582.https://digitalcommons.colby.edu/honorstheses/582
Copyright
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Comments
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