Project description:Two-dimensional patterning of the follicular epithelium in Drosophila oogenesis is required for the formation of three-dimensional eggshell structures. Our analysis of a large number of published gene expression patterns in the follicle cells suggests that they follow a simple combinatorial code based on six spatial building blocks and the operations of union, difference, intersection, and addition. The building blocks are related to the distribution of inductive signals, provided by the highly conserved epidermal growth factor receptor and Decapentaplegic (DPP) pathways. We demonstrate the validity of the code by testing it against a set of patterns obtained in a large-scale transcriptional profiling experiment. Using the proposed code, we distinguish 36 distinct patterns for 81 genes expressed in the follicular epithelium and characterize their joint dynamics over four stages of oogenesis. The proposed combinatorial framework allows systematic analysis of the diversity and dynamics of two-dimensional transcriptional patterns and guides future studies of gene regulation. Keywords: EGFR, BMP, gain/loss-of-function
Project description:Two-dimensional patterning of the follicular epithelium in Drosophila oogenesis is required for the formation of three-dimensional eggshell structures. Our analysis of a large number of published gene expression patterns in the follicle cells suggests that they follow a simple combinatorial code based on six spatial building blocks and the operations of union, difference, intersection, and addition. The building blocks are related to the distribution of inductive signals, provided by the highly conserved epidermal growth factor receptor and Decapentaplegic (DPP) pathways. We demonstrate the validity of the code by testing it against a set of patterns obtained in a large-scale transcriptional profiling experiment. Using the proposed code, we distinguish 36 distinct patterns for 81 genes expressed in the follicular epithelium and characterize their joint dynamics over four stages of oogenesis. The proposed combinatorial framework allows systematic analysis of the diversity and dynamics of two-dimensional transcriptional patterns and guides future studies of gene regulation. Keywords: EGFR, BMP, gain/loss-of-function RNA was isolated from hand dissected, stage 9-10 egg chambers. Five genetic backgrounds were profiled including: wild type, EGFR gain of function, EGFR loss of function, BMP gain of function, and BMP loss of function. Three biological replicates were hybridized for each pathway perturbation. The samples were split across two rounds of hybridization. Each round of hybridizations included three biological replicates for wild type: The first round included EGFR gof, EGFR lof, BMP gof, and wild type controls A1-A3 (GSM313514-16). For these 12 arrays the extraction, labeling, and hybridization steps were done in parallel. The second round included the BMP lof and wild type controls B1-B3 (GSM313517-19). For these 6 arrays, the extraction, labeling, and hybridization steps were done in parallel.
Project description:Despite the importance of egg development to the female life cycle in Drosophila, global patterns of gene expression have not been examined in detail primarily due to the difficulty of synchronizing developmental stages. Entry into vitellogenesis is however an key stage of oogenesis, and by delaying entry past this control point, we have been able to investigate some of the transcriptional dynamics apparent before and after early egg formation over a 72 hour period.
Project description:The binding patterns of some transcription factors have been shown to diverge substantially between closely related species. Here, we show that the binding pattern of the developmental transcription factor Twist is highly conserved across six Drosophila species, revealing strong functional constraints at developmental enhancers. Conserved binding correlates with sequence motifs for Twist and its partners, permitting the de novo discovery of their cooperative binding. It also includes over 10,000 low-occupancy sites near the detection limit, which tend to mark enhancers of later developmental stages. We predict that conservation, dynamic occupancy, and combinatorial regulation will be generally true for developmental enhancers.
Project description:Transfer RNAs (tRNAs) are the adaptor molecules required for reading of the genetic code and the accurate production of proteins. tRNA variants can lead to genome-wide mistranslation, the misincorporation of amino acids not specified by the standard genetic code, into nascent proteins. While genome sequencing has identified putative mistranslating tRNA variants in human populations, little is known regarding how mistranslation affects multicellular organisms. Here, we create a Drosophila melanogaster model for mistranslation by integrating a serine tRNA variant that mistranslates serine for proline (tRNA(Ser)[UGG, G26A]) into the fly genome. Using mass spectrometry, we find that tRNA(Ser)[UGG, G26A] misincorporates serine for proline at a frequency of ~ 0.6% per codon. This model will enable studies into the synergistic effects of mistranslating tRNA variants and disease-causing alleles.