Dataset Information

A combinatorial enhancer recognized by Mad, TCF and Brinker first activates then represses dpp expression in the posterior spiracles of Drosophila.

ABSTRACT: A previous genetic analysis of a reporter gene carrying a 375-bp region from a dpp intron (dppMX-lacZ) revealed that the Wingless and Dpp pathways are required to activate dpp expression in posterior spiracle formation. Here we report that within the dppMX region there is an enhancer with binding sites for TCF and Mad that are essential for activating dppMX expression in posterior spiracles. There is also a binding site for Brinker likely employed to repress dppMX expression. This combinatorial enhancer may be the first identified with the ability to integrate temporally distinct positive (TCF and Mad) and negative (Brinker) inputs in the same cells. Cuticle studies on a unique dpp mutant lacking this enhancer showed that it is required for viability and that the Filzkorper are U-shaped rather than straight. Together with gene expression data from these mutants and from brk mutants, our results suggest that there are two rounds of Dpp signaling in posterior spiracle development. The first round is associated with dorsal-ventral patterning and is necessary for designating the posterior spiracle field. The second is governed by the combinatorial enhancer and begins during germ band retraction. The second round appears necessary for proper spiracle internal morphology and fusion with the remainder of the tracheal system. Intriguingly, several aspects of dpp posterior spiracle expression and function are similar to demonstrated roles for Wnt and BMP signaling in proximal-distal outgrowth of the mammalian embryonic lung.

SUBMITTER: Takaesu NT

PROVIDER: S-EPMC2254533 | biostudies-literature | 2008 Jan

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

A combinatorial enhancer recognized by Mad, TCF and Brinker first activates then represses dpp expression in the posterior spiracles of Drosophila.

Takaesu Norma T NT Bulanin Denis S DS Johnson Aaron N AN Orenic Teresa V TV Newfeld Stuart J SJ

Developmental biology 20071024 2

A previous genetic analysis of a reporter gene carrying a 375-bp region from a dpp intron (dppMX-lacZ) revealed that the Wingless and Dpp pathways are required to activate dpp expression in posterior spiracle formation. Here we report that within the dppMX region there is an enhancer with binding sites for TCF and Mad that are essential for activating dppMX expression in posterior spiracles. There is also a binding site for Brinker likely employed to repress dppMX expression. This combinatorial ...[more]

PMID: 18068697

Similar Datasets

Project description:C/EBPα plays a key role in specifying myeloid lineage development. HoxA9 is expressed in myeloid progenitors, with its level diminishing during myeloid maturation, and HOXA9 is over-expressed in a majority of acute myeloid leukemia cases, including those expressing NUP98-HOXD13. The objective of this study was to determine whether HoxA9 directly represses Cebpa gene expression. We find 4-fold increased HoxA9 and 5-fold reduced Cebpa in marrow common myeloid and LSK progenitors from Vav-NUP98-HOXD13 transgenic mice. Conversely, HoxA9 decreases 5-fold while Cebpa increases during granulocytic differentiation of 32Dcl3 myeloid cells. Activation of exogenous HoxA9-ER in 32Dcl3 cells reduces Cebpa mRNA even in the presence of cycloheximide, suggesting direct repression. Cebpa transcription in murine myeloid cells is regulated by a hematopoietic-specific +37 kb enhancer and by a more widely active +8 kb enhancer. ChIP-Seq analysis of primary myeloid progenitor cells expressing exogenous HoxA9 or HoxA9-ER demonstrates that HoxA9 localizes to both the +8 kb and +37 kb Cebpa enhancers. Gel shift analysis demonstrates HoxA9 binding to three consensus sites in the +8 kb enhancer, but no affinity for the single near-consensus site present in the +37 kb enhancer. Activity of a Cebpa +8 kb enhancer/promoter-luciferase reporter in 32Dcl3 or MOLM14 myeloid cells is increased ~2-fold by mutation of its three HOXA9-binding sites, suggesting that endogenous HoxA9 represses +8 kb Cebpa enhancer activity. In contrast, mutation of five C/EBPα-binding sites in the +8 kb enhancer reduces activity 3-fold. Finally, expression of a +37 kb enhancer/promoter-hCD4 transgene reporter is reduced ~2-fold in marrow common myeloid progenitors when the Vav-NUP98-HOXD13 transgene is introduced. Overall, these data support the conclusion that HoxA9 represses Cebpa expression, at least in part via inhibition of its +8 kb enhancer, potentially allowing normal myeloid progenitors to maintain immaturity and contributing to the pathogenesis of acute myeloid leukemia associated with increased HOXA9.

Project description:Forensic entomology is the branch of forensic science that is related to using arthropod specimens found in legal issues. Fly maggots are one of crucial pieces of evidence that can be used for estimating post-mortem intervals worldwide. However, the species-level identification of fly maggots is difficult, time consuming, and requires specialized taxonomic training. In this work, a novel method for the identification of different forensically-important fly species is proposed using convolutional neural networks (CNNs). The data used for the experiment were obtained from a digital camera connected to a compound microscope. We compared the performance of four widely used models that vary in complexity of architecture to evaluate tradeoffs in accuracy and speed for species classification including ResNet-101, Densenet161, Vgg19_bn, and AlexNet. In the validation step, all of the studied models provided 100% accuracy for identifying maggots of 4 species including Chrysomya megacephala (Diptera: Calliphoridae), Chrysomya (Achoetandrus) rufifacies (Diptera: Calliphoridae), Lucilia cuprina (Diptera: Calliphoridae), and Musca domestica (Diptera: Muscidae) based on images of posterior spiracles. However, AlexNet showed the fastest speed to process the identification model and presented a good balance between performance and speed. Therefore, the AlexNet model was selected for the testing step. The results of the confusion matrix of AlexNet showed that misclassification was found between C. megacephala and C. (Achoetandrus) rufifacies as well as between C. megacephala and L. cuprina. No misclassification was found for M. domestica. In addition, we created a web-application platform called thefly.ai to help users identify species of fly maggots in their own images using our classification model. The results from this study can be applied to identify further species by using other types of images. This model can also be used in the development of identification features in mobile applications. This study is a crucial step for integrating information from biology and AI-technology to develop a novel platform for use in forensic investigation.

Dataset Information

A combinatorial enhancer recognized by Mad, TCF and Brinker first activates then represses dpp expression in the posterior spiracles of Drosophila.

Publications

A combinatorial enhancer recognized by Mad, TCF and Brinker first activates then represses dpp expression in the posterior spiracles of Drosophila.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets