Project description:The lymph gland is one of the main larval hematopoietic organin in Drosophila melanogaster. In wnandering third instar larav, it is composed of two pairs of anterior lobes, followed by 2 to 3 pair of posterior lobes. To gain further insight into the gene expression repertoire of Drosophila blood cells, we established the gene expression profiles of third instar larva lymph glands anterior and posterior lobes.
Project description:The balance between hematopoietic progenitors and differentiated hemocytes is finely tuned during development. In the larval hematopoietic organ of Drosophila, called the lymph gland, the receptor tyrosine kinase Pvr signals from differentiated cells to maintain a pool of undifferentiated progenitors. However, little is known about the processes that support Pvr function. The small GTPase Ral is involved in the regulation of several membrane trafficking events. Drosophila has a single Ral protein, Rala, which has been implicated in the development of various tissues. Here, we investigated the involvement of Rala in the larval fly hematopoietic system. We discovered that the loss of Rala activity phenocopies Pvr loss of function by promoting hemocyte progenitor differentiation. Moreover, using epistasis analysis, we found that the guanine exchange factor RalGPS lies upstream of Rala in this event, whereas the exocyst and Rab11 are acting downstream. Strikingly, the loss of Rala activity leads to a considerable accumulation of Pvr at the plasma membrane, hence suggesting a trafficking defect and reduced Pvr function. Consistent with this hypothesis, Rala loss of function phenotype in the lymph gland is fully suppressed by constitutive STAT activity, which normally mediates Pvr function in the lymph gland. Together, our findings unravel a novel RalGPS-Rala-exocyst-Rab11 axis for the maintenance of lymph gland homeostasis through Pvr.
Project description:Drosophila adult blood cells originate from larval peripheral hemocytes (derived from the embryonic waves of hematopoiesis) and from larval lymph gland hemocytes. To gain insight into the expression repertoire of Drosophila blood cells, we established the gene expression profiles the adult blood cells and their ascendants.
Project description:This SuperSeries is composed of the following subset Series:; GSE8619: Senseless-responsive genes in larval salivary glands of late Drosophila prepupae; GSE8620: GAL4-responsive genes in larval salivary glands of late Drosophila prepupae Experiment Overall Design: Refer to individual Series
Project description:When misexpressed in late Drosophila prepupae, the transcription factor Senseless (Sens) blocks death of the larval salivary glands that normally occurs in the early pupa. The aim of the experiment was to identify genes responding to Sens that might mediate the effect of the protein on cell death and other biological processes. The yeast transcription factor GAL4, expressed from a heat-inducible transgene (P{GAL4-Hsp70.PB}89-2-1), was used to drive expression of Sens from a UAS-sens transgene. After crossing the GAL4 and UAS lines, expression of GAL4 was induced by a 30-min heat shock treatment (37 °C) of the progeny at 9 hours after puparium formation. Salivary glands were dissected at 14 hours after puparium formation and RNA isolated for microarray analysis with Affymetrix GeneChips. Control samples were obtained from animals treated the same way carrying one copy of the GAL4 transgene (progeny of a cross between flies of the P{GAL4-Hsp70.PB}89-2-1 and w1118 strains) and w1118 animals. The microarray data identified several genes associated with programmed cell death, including caspase genes, which respond to Sens. In addition, the data show that many Drosophila genes respond to the yeast transcription factor GAL4 in a UAS-independent manner. To identify target genes of Sens that are of biological relevance, gene expression patterns in the presence of Sens were compared to gene expression patterns in both the presence and the absence of GAL4. This comparison revealed that Sens seems to preferentially downregulate targets that are upregulated by GAL4, suggesting that these genes may not necessarily constitute true transcriptional targets of Sens. Keywords: ectopic expression experiment
Project description:When misexpressed in late Drosophila prepupae, the transcription factor Fork head (Fkh) blocks death of the larval salivary glands that normally occurs in the early pupa. The aim of the experiment was to identify genes responding to Fkh that might mediate the effect of the protein on cell death and other biological processes. Fkh was expressed in the line P[hs-Fkh111] from a heat-inducible transgene that encodes wild-type Fkh protein. Expression of Fkh was induced by incubating prepupae for 30 min in a 37 °C water bath, starting at 9.5 hours after puparium formation. Salivary glands were dissected at 14 hours after puparium formation and RNA isolated for microarray analysis with Affymetrix GeneChips. Control samples were obtained from w1118 animals treated the same way. The microarray analysis identified 55 genes annotated as functioning in apoptosis whose expression was at least 1.5-fold changed by Fkh. These genes include the death genes hid and reaper, which play a central role in the control of salivary gland death. Other groups of significantly enriched genes include genes functioning in autophagy, steroid-signaling pathways, salivary gland secretion, and phospholipid metabolism. In addition, the microarray data identify genes as responsive to Fkh that are known to be controlled by the FOXA counterparts of Fkh in vertebrates, indicating that target genes and biological processes controlled by Fkh are evolutionarily conserved. Keywords: ectopic expression experiment
Project description:kdm5 is an essential gene in Drosophila that has critical developmental roles in the prothoracic gland cells of the larval ring gland. We performed a bulk transcriptome analysis of the larval ring gland in w[1118] (wild type) and kdm5[140] (null mutant) in order to identify genes in the prothoracic gland involved in the lethality of kdm5 null mutants. We found that the absence of kdm5 causes dysregulation of genes involved in various metabolic pathways. In particular, genes both bound by KDM5 and differentially expressed in this cell type are involved in regulation of mitochondrial biology and autophagy.