Homeotic Genes

Castelli-Gair, James

doi:10.1002/047120918x.emb0678

Cited by 5 publications

(12 citation statements)

References 17 publications

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“…The activity of the Drosophila JAK/STAT pathway is required for multiple processes during embryonic, larval and adult life where it produces diverse developmental, transcriptional and cell biological effects (reviewed in Castelli-Gair Hombrı´a and Brown, 2002;Hou et al, 2002). This report is the first in which the role of the pathway in controlling cellular proliferation has been studied in detail and we have used the context of the developing wing imaginal disc as an in vivo system.…”

Section: Discussionmentioning

confidence: 99%

“…We first examined the Upd ligand, a secreted glycoprotein (Harrison et al, 1998), whose expression is closely associated with almost all examples of pathway activity described to date (for review, see Castelli-Gair Hombrı´a and Brown, 2002). During early and late second instar wing development, upd is detected in a large domain within the future dorsal hinge (Figure 3a, b).…”

Section: Noncanonical Stat92e Activationmentioning

confidence: 99%

“…The JAK/STAT pathway has been conserved through evolution and is present in the fruit fly Drosophila melanogaster (Castelli-Gair Hombrı´a and Brown, 2002). In flies an extracellular ligand Unpaired (Upd: Harrison et al, 1998), a trans-membrane receptor, Domeless (Dome: Brown et al, 2001;Chen et al, 2002), a JAK tyrosine kinase called Hopscotch (Hop: Binari and Perrimon, 1994) and the STAT92E transcription factor (Hou et al, 1996;Yan et al, 1996) make up the pathway.…”

Section: Introductionmentioning

confidence: 99%

“…In flies an extracellular ligand Unpaired (Upd: Harrison et al, 1998), a trans-membrane receptor, Domeless (Dome: Brown et al, 2001;Chen et al, 2002), a JAK tyrosine kinase called Hopscotch (Hop: Binari and Perrimon, 1994) and the STAT92E transcription factor (Hou et al, 1996;Yan et al, 1996) make up the pathway. The identification of mutations in all components, in combination with the developmental genetics of the Drosophila system have lead to the identification of multiple embryonic, larval and adult developmental processes which require the pathway (reviewed in Castelli-Gair Hombrı´a and Brown, 2002;Hou et al, 2002).…”

Section: Introductionmentioning

confidence: 99%

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Opposing roles for Drosophila JAK/STAT signalling during cellular proliferation

2005

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The JAK/STAT signalling pathway mediates both antiproliferative responses following interferon stimulation and cellular proliferation in response to cytokines such as interleukins and growth factors. Central to these responses are the seven vertebrate STAT molecules, misregulation of which is implicated in a variety of malignancies. We have investigated the proliferative role of the single Drosophila STAT92E, part of the evolutionarily conserved JAK/STAT cascade. During second instar larval wing disc development pathway activity is both necessary and sufficient to promote proliferation of this epithelial cell type. However by later stages, endogenous STAT92E is stimulated by a noncannonical mechanism to exert pronounced antiproliferative effects. Ectopic canonical activation is sufficient to further decrease proliferation and leads to the premature arrest of cells in the G2 phase of the cell cycle. The single STAT92E present in Drosophila therefore mediates both proproliferative functions analogous to vertebrate interleukin-stimulated STAT3 and antiproliferative functions analogous to interferon-stimulated STAT1. Pro-and antiproliferative roles therefore represent ancestral activities conserved through evolution and subsequently assigned to distinct molecules.

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Section: Discussionmentioning

confidence: 99%

Section: Noncanonical Stat92e Activationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Opposing roles for Drosophila JAK/STAT signalling during cellular proliferation

2005

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“…In Drosophila, the homeotic gene Ubx has two main functions. Whereas early Ubx expression initiates abdominal development, at later stages Ubx is also required for proper development of the T3 segment including the leg and wing appendages (9)(10)(11). In addition, a recent study of related Drosophila species shows that differential Ubx expression is directly regulating the fine-scale morphological differences (such as bristle pattern) between T3 and T2 legs (12).…”

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confidence: 99%

Differential expression patterns of the hox gene are associated with differential growth of insect hind legs

Mahfooz

Popadić

2004

Proc. Natl. Acad. Sci. U.S.A.

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Diversification of leg appendages is one of the hallmarks of morphological evolution in insects. In particular, insect hind (T3) legs exhibit a whole spectrum of morphological diversification, ranging from uniform to extremely modified. To elucidate the developmental basis of T3 leg evolution, we have examined the expression patterns of two homeotic genes, Ultrabithorax and abdominal-A (collectively referred to as UbdA), in a broad range of species. First, our results show that UbdA expression in hemimetabolous insects is localized only in specific T3 leg segments undergoing differential growth (compared to their foreleg counterparts). In contrast, in basal hexapod and insect lineages, the absence of the UbdA signal coincides with uniform leg morphology. The same situation exists in first instar larvae of holometabolous insects, in which absence of UbdA expression in the embryonic T3 legs is associated with the lack of larval T3 leg diversification. Second, there is a clear difference in the timing of expression between species with greatly enlarged T3 leg, such as crickets and grasshoppers, and species that exhibit more moderate enlargement of hind legs, such as mantids and cockroaches. In the former, the UbdA expression starts much earlier, coinciding with the elongation of T3 limb buds. In the latter, however, the UbdA expression starts at much later stages of development, coinciding with the establishment of distinct leg segments. These results suggest that diversification of insect hind legs was influenced by changes in both the spatial and temporal regulation of the UbdA expression.

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A functional genomic screen for cardiogenic genes using RNA interference in developing Drosophila embryos

Kim

Park

Balaban

et al. 2003

Proc. Natl. Acad. Sci. U.S.A.

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Identifying genetic components is an essential step toward understanding complex developmental processes. The primitive heart of the fruit fly, the dorsal vessel, which is a hemolymph-pumping organ, has provided a unique model system to identify cardiogenic genes and to further our understanding of the molecular mechanisms of cardiogenesis. Using RNA interference in developing Drosophila embryos, we performed a genomewide search for cardiogenic genes. Through analyses of the >5,800 genes that cover Ϸ40% of all predicted Drosophila genes, we identified a variety of genes encoding transcription factors and cell signaling proteins required for different steps during heart development. Analysis of mutant heart phenotypes and identified genes suggests that the Drosophila heart tube is segmentally patterned, like axial patterning, but assembled with regional modules. One of the identified genes, simjang, was further characterized. In the simjang mutant embryo, we found that within each segment a subset of cardial cells is missing. Interestingly, the simjang gene encodes a protein that is a component of the chromatin remodeling complex recruited by methyl-CpG-DNA binding proteins, suggesting that epigenetic information is crucial for specifying cardiac precursors. Together, these studies not only identify key regulators but also reveal mechanisms underlying heart development. O ver the last decade significant progress has been made in our understanding of the molecular details of cardiac morphogenesis. These advances can be attributed to the fact that many embryonic events involved in cardiogenesis are remarkably conserved among distinct species (1-3). In the Drosophila embryo, bilaterally symmetric groups of cardiac precursor cells in the dorsal-most mesoderm, specified by positional information provided by intrinsic cell-autonomous factors and extrinsic signals, meet in the dorsal midline to form a linear heart tube (3). Unlike the vertebrate linear heart tube, which proceeds further to looping and multichamber formation, the Drosophila heart remains a contractile linear tube at maturity. Two major classes of cell observed within the Drosophila cardiogenic repertoire are cardial cells (cardioblasts), which form the lumen of the linear heart tube, and pericardial cells, which flank and are associated with cardial cells (4). Cardial cells eventually form the cardiac muscles and are the contractile cells of the heart, whereas pericardial cells do not express muscle proteins but may function in hemolymph filtration. The linear heart tube shows clear structural differences along its length after its formation in late embryogenesis. The posterior three segments constitute the heart, a contractile tube with a wide bore involved in the forward pumping of hemolymph. Three pairs of specialized inflow valves (ostia) are present in the heart to facilitate the lateral entry of hemolymph (5, 6). Anterior to the heart is a narrower section, termed the aorta, that encompasses four segments. Despite its apparently simple structure an...

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Homeotic Genes

Cited by 5 publications

References 17 publications

Opposing roles for Drosophila JAK/STAT signalling during cellular proliferation

Opposing roles for Drosophila JAK/STAT signalling during cellular proliferation

Differential expression patterns of the hox gene are associated with differential growth of insect hind legs

A functional genomic screen for cardiogenic genes using RNA interference in developing Drosophila embryos

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