You will be shown an abstract from a biomedical research paper. Given this abstract, your task is to extract all unique entities of the following types: ["Chemical"].

Please return the output as a JSON object of the format: {"Chemical": ["Arsenic", ...]}. The keys should be entity types and values should be lists of extracted entities belonging to the corresponding type. If you cannot find entities belonging to a specific type, the value should be [].

Only output the JSON object and do not include any additional text.

Abstract:

The binding of multiple nuclear receptors to a single regulatory region is important for the proper expression of EDG84A in Drosophila melanogaster. Nuclear receptor transcription factor family members share target sequence similarity; however, little is known about how these factors exert their specific regulatory control. Here, we examine the mechanism regulating the expression of the Drosophila EDG84A gene, a target gene of the orphan nuclear receptor βFTZ-F1, as a model to study the cooperative behavior among nuclear receptors. We show that the three nuclear receptors βFTZ-F1, DHR3, and DHR39 bind to a common element in the EDG84A promoter. The expression level of the EDG84A promoter-lacZ reporter genes in DHR39-induced and mutant animals, respectively, suggests that DHR39 works as a repressor. The activity of a reporter gene carrying a mutation preventing DHR3 binding was reduced in ftz-f1 mutants and rescued by the induced expression of βFTZ-F1, suggesting that DHR3 and βFTZ-F1 activate the EDG84A gene in a redundant manner. A reporter gene carrying a mutation that abolishes DHR39 and FTZ-F1 binding was prematurely expressed, and the expression level of the reporter gene carrying a mutation preventing DHR3 binding was reduced. These findings suggest that the temporal expression of this gene is mainly controlled by βFTZ-F1 but that the binding of DHR3 is also important. Comparison of the binding site sequence among Drosophila species suggests that DHR3 binding ability was gained after the melanogaster subgroup evolved, and this ability may contribute to the robust expression of this gene. These results show the complicated regulatory mechanisms utilized by multiple nuclear receptors to properly regulate the expression of their target gene through a single target site.
{"Chemical": []}