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We have screened a collection of UAS-RNAi lines targeting 10,920 Drosophila protein-coding genes for phenotypes in the adult wing. We identified 3653 genes (33%) whose knockdown causes either larval/pupal lethality or a mutant phenotype affecting the formation of a normal wing. The most frequent phenotypes consist of changes in wing size, vein differentiation, and patterning, defects in the wing margin and in the apposition of the dorsal and ventral wing surfaces. We also defined 16 functional categories encompassing the most relevant aspect of each protein function and assigned each Drosophila gene to one of these functional groups. This allowed us to identify which mutant phenotypes are enriched within each functional group. Finally, we used previously published gene expression datasets to determine which genes are or are not expressed in the wing disc. Integrating expression, phenotypic and molecular information offers considerable precision to identify the relevant genes affecting wing formation and the biological processes regulated by them., (© The Author(s) 2021. Published by Oxford University Press on behalf of Genetics Society of America.)

The Drosophila genome contains approximately 14,000 protein-coding genes encoding all the necessary information to sustain cellular physiology, tissue organization, organism development, and behavior. In this manuscript, we describe in some detail the phenotypes in the adult fly wing generated after knockdown of approximately 80% of Drosophila genes. We combined this phenotypic description with a comprehensive molecular classification of the Drosophila proteins into classes that summarize the main expected or known biochemical/functional aspect of each protein. This information, combined with mRNA expression levels and in situ expression patterns, provides a simplified atlas of the Drosophila genome, from housekeeping proteins to the components of the signaling pathways directing wing development, that might help to further understand the contribution of each gene group to wing formation., (© The Author(s) 2021. Published by Oxford University Press on behalf of Genetics Society of America.)

Embryonic stem cell (ESC) differentiation and somatic cell reprogramming are biological processes governed by antagonistic expression or repression of a largely common set of genes. Accurate regulation of gene expression is thus essential for both processes, and alterations in RNA processing are predicted to negatively affect both. We show that truncation of the DIDO gene alters RNA splicing and transcription termination in ESC and mouse embryo fibroblasts (MEF), which affects genes involved in both differentiation and reprogramming. We combined transcriptomic, protein interaction, and cellular studies to identify the underlying molecular mechanism. We found that DIDO3 interacts with the helicase DHX9, which is involved in R-loop processing and transcription termination, and that DIDO3-exon16 deletion increases nuclear R-loop content and causes DNA replication stress. Overall, these defects result in failure of ESC to differentiate and of MEF to be reprogrammed. MEF immortalization restored impaired reprogramming capacity. We conclude that DIDO3 has essential functions in ESC differentiation and somatic cell reprogramming by supporting accurate RNA metabolism, with its exon16-encoded domain playing the main role.

Transition from symmetric to asymmetric cell division requires precise coordination of differential gene expression. We show that embryonic stem cells (ESCs) mainly express DIDO3 and that their differentiation after leukemia inhibitory factor withdrawal requires DIDO1 expression. C-terminal truncation of DIDO3 (Dido3ΔCT) impedes ESC differentiation while retaining self-renewal; small hairpin RNA-Dido1 ESCs have the same phenotype. Dido3ΔCT ESC differentiation is rescued by ectopic expression of DIDO3, which binds the Dido locus via H3K4me3 and RNA POL II and induces DIDO1 expression. DIDO1, which is exported to cytoplasm, associates with, and is N-terminally phosphorylated by PKCiota. It binds the E3 ubiquitin ligase WWP2, which contributes to cell fate by OCT4 degradation, to allow expression of primitive endoderm (PE) markers. PE formation also depends on phosphorylated DIDO3 localization to centrosomes, which ensures their correct positioning for PE cell polarization. We propose that DIDO isoforms act as a switchboard that regulates genetic programs for ESC transition from pluripotency maintenance to promotion of differentiation., (Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.)

Vinal-derived Activated Carbon (VAC) developed by phosphoric acid activation of sawdust from Prosopis ruscifolia native wood was tested for the adsorption of Ni(II) ions from dilute solutions in both batch and dynamic modes, comparing it with a Commercial Activated Carbon (CAC). Batch experiments were performed to determine adsorption kinetics and equilibrium isotherms for both carbons. It was possible to remove near 6.55 mg Ni g(-1) VAC and 7.65 mg Ni g(-1) CAC after 5 h and 10 h contact time, respectively. A pseudo second order equation fitted well with the kinetics of the process, and Langmuir adsorption model was used to adjust the experimental results concerning the adsorption isotherm. The parameters obtained indicate a stronger interaction between sorbent and sorbate for VAC (K = 26.56 L mmol(-1)) than for CAC (K = 19.54 L mmol(-1)). Continuous experiments were performed in a fixed-bed column packed with the investigated carbons, evaluating the influence of operational parameters such as flow rate, bed height and feed concentration on the breakthrough curves obtained. The breakthrough occurred more slowly for low concentrations of the metal ion in the feed, low flow rates and high bed height. The breakthrough curves were properly represented by Hall's model for both carbon types. Regeneration of the vinal activated carbon in column was tested, obtaining the same breakthrough curve in a new cycle of use. Finally, vinal-derived activated carbon can effectively be used to treat wastewater having until 30 ppm Ni(II)., (Copyright © 2011 Elsevier Ltd. All rights reserved.)

The formation of photoreceptor cells (PRCs) in Drosophila serves as a paradigm for understanding neuronal determination and differentiation. During larval stages, a precise series of sequential inductive processes leads to the recruitment of eight distinct PRCs (R1-R8). But, final photoreceptor differentiation, including rhabdomere morphogenesis and opsin expression, is completed four days later, during pupal development. It is thought that photoreceptor cell fate is irreversibly established during larval development, when each photoreceptor expresses a particular set of transcriptional regulators and sends its projection to different layers of the optic lobes. Here, we show that the spalt (sal) gene complex encodes two transcription factors that are required late in pupation for photoreceptor differentiation. In the absence of the sal complex, rhabdomere morphology and expression of opsin genes in the inner PRCs R7 and R8 are changed to become identical to those of outer R1-R6 PRCs. However, these cells maintain their normal projections to the medulla part of the optic lobe, and not to the lamina where outer PRCs project. These data indicate that photoreceptor differentiation occurs as a two-step process. First, during larval development, the photoreceptor neurons become committed and send their axonal projections to their targets in the brain. Second, terminal differentiation is executed during pupal development and the photoreceptors adopt their final cellular properties.

Spalt and Spalt-related encode conserved Zn-finger proteins that mediate the function of the TGF-beta molecule Decapentaplegic during the positioning of veins in the Drosophila wing. Here we show that Spalt and Spalt-related regulate the vein-specific expression of the transcription factors of the knirps and iroquois gene complexes, delimiting their domains of expression in the wing pouch. The effects of spalt/spalt-related mutations on knirps and iroquois expression are cell-autonomous, suggesting that they could be direct. The regulation of iroquois involves transcriptional repression by Spalt and Spalt-related, whereas the regulation of knirps involves a combination of transcriptional activation and repression mediated by the same genes. We suggest that the regulation of the iroquois and knirps gene complexes by Spalt and Spalt-related translates the Decapentaplegic morphogenetic gradient into precisely spaced pattern elements.

The zinc finger transcription factors Spalt and Spalt-related have been implicated in multiple developmental processes. In the wing they are regulated by the secreted protein Decapentaplegic and participate in the positioning of the wing veins. The function of Spalt has been also analyzed during tracheal development and embryonic segmentation. Here, we present the isolation and characterization of novel spalt/spalt-related alleles, which analysis indicates that these genes cannot substitute for each other in the developmental processes studied. The mutants present embryonic or pupal lethality, with phenotypes consistent with the loss of spalt function. We also present a detailed functional analysis of the DNA regions implicated in the regulation of these genes. This regulation is complex, integrating the information from both negative and positive regulators, and it is modular, with discrete fragments of DNA directing expression to discrete regions in embryonic and larval tissues., (Copyright 1999 Academic Press.)

The activities of conserved signal transduction pathways are central to the development of Drosophila wings, legs, and eyes. Yet, all these structures have characteristic morphologies, suggesting that additional factors provide organ-specific information. One excellent candidate for such a function is Vestigial, which activity promotes the formation of wings. The biochemical function of Vestigial is unknown, however, since no homologies with other proteins have been identified. Two recent reports show that Vestigial interacts with the transcription factor Scalloped, forming an active complex that binds to specific DNA sequences and regulates gene expression in cooperation with several signalling pathways. These results illustrate how tissue-specific transcription factors cooperate with general signalling pathways to regulate gene expression in a tissue-specific manner.

In the Drosophila compound eye the dorsal and ventral fields of eye units (ommatidia) meet along the dorsoventral midline, forming a line of mirror image symmetry called the equator. The molecular mechanism establishing the equator is not fully understood, but it involves the transcription factors encoded by the Iroquois gene complex. The Iroquois genes are expressed in the dorsal half of the eye and here we show that they regulate the expression of the secreted molecule Fringe. A boundary between fringe-expressing and fringe-non-expressing cells is essential, from the time of the second larval instar, for eye growth and formation of the equator. Boundaries of fringe expression determine where the transmembrane receptor Notch is activated. We find that Notch is activated at the dorsoventral midline, where it is required to promote growth and set up the axis of mirror symmetry. As boundaries of fringe expression and Notch activation are also important during Drosophila wing formation and vertebrate somitogenesis, we suggest that these boundaries constitute a general mechanism that directs growth and patterning of large fields of cells.

Morphogenesis is the process by which structures with characteristic sizes, proportions and patterns of cell differentiation are generated during the development of multicellular organisms. How the elaboration of pattern is related to cell proliferation and growth control is a critical aspect of morphogenesis. The imaginal discs of Drosophila are a suitable model in which this can be investigated at cellular and molecular level, and recent genetic and developmental analysis has identified some of the key genes and mechanisms that participate in the regulation of their growth and patterning. This review will focus on the formation of the venation pattern in the adult wing, particularly on: 1) the subdivision of the wing blade into domains of gene expression that position the veins, and 2) the cell-cell signaling pathways that participate in the final differentiation of veins.

Localized expression of the transforming growth factor-beta (TGF-beta) homologue decapentaplegic (dpp) is crucial for Drosophila wing development. Here we show that spalt and spalt-related (sal and salr), two closely related genes that encode transcription factors, are expressed in response to dpp in a central territory of the wing imaginal disc, where they are required for the patterning of the wing. They are among the first identified elements that act downstream of dpp in wing development. The phenotypic consequences of misexpression of sal and salr suggest that an important outcome of dpp activity is the subdivision of the wing disc into territories smaller than lineage compartments, through the regulation of transcription-factor-encoding genes such as sal and salr.

The gene extramacrochaetae (emc) encodes a non-basic Helix-loop-helix (HLH) protein that interacts and antagonises other basic-HLH proteins. The expression pattern of emc, and the phenotype of lethal emc alleles indicate that this gene is operative in several developmental processes. Here we study the requirements for emc during cell proliferation and vein differentiation in the wing. Mosaic analysis of hypomorphic conditions of emc reveals the tendency of mutant cells to proliferate along the veins as long stripes. Large clones abuting two adjacent veins obliterate the corresponding inter-vein, affecting the size and shape of the whole wing. Thus, the emc gene participates in the control of cell proliferation within inter-vein regions in the wing. Similar effects were found in the haltere and in the leg. The behavior of emc cells in genetic mosaics indicate that (1) proliferation is locally controlled within inter-vein sectors, (2) cells proliferate according to their genetic activity along preferential positions in the wing morphogenetic landscape and (3) cell proliferation in the wing is integrated by 'accommodation' between mutant and wild type cells.

The Notch gene encodes a transmembrane protein that functions as a receptor of intercellular signals in many developmental processes of Drosophila. We study here the Notch function in wing morphogenesis and vein patterning in genetic mosaics of both Notch null and Notch gain-of-function alleles. Cell proliferation and differentiation properties of mutant Notch cells define three different Notch requirements in the wing: in imaginal disc cell proliferation, in restriction of vein differentiation and in margin formation. The study of Notch mosaics in different mutant backgrounds reveals that Notch activity during epidermal cell proliferation and wing vein differentiation is exerted by its regulation of a common group of genes involved in the specification and restriction of vein competent regions.