scholarly journals Expression of wingless in the Drosophila embryo: a conserved cis-acting element lacking conserved Ci-binding sites is required for patched-mediated repression

Development ◽  
1998 ◽  
Vol 125 (8) ◽  
pp. 1469-1476 ◽  
Author(s):  
D. Lessing ◽  
R. Nusse
Keyword(s):  
Binding Sites ◽  
Transmembrane Protein ◽  
Cell Communication ◽  
Signal Transduction Pathway ◽  
Transcription Unit ◽  
Drosophila Virilis ◽  
Negative Regulator ◽  
Drosophila Embryo ◽  
Cis Acting ◽  
Hh Signaling

Patterning of the Drosophila embryo depends on the accurate expression of wingless (wg), which encodes a secreted signal required for segmentation and many other processes. Early expression of wg is regulated by the nuclear proteins of the gap and pair-rule gene classes but, after gastrulation, wg transcription is also dependent on cell-cell communication. Signaling to the Wg-producing cells is mediated by the secreted protein, Hedgehog (Hh), and by Cubitus interruptus (Ci), a transcriptional effector of the Hh signal transduction pathway. The transmembrane protein Patched (Ptc) acts as a negative regulator of wg expression; ptc- embryos have ectopic wg expression. According to the current models, Ptc is a receptor for Hh. The default activity of Ptc is to inhibit Ci function; when Ptc binds Hh, this inhibition is released and Ci can control wg transcription. We have investigated cis-acting sequences that regulate wg during the time that wg expression depends on Hh signaling. We show that approximately 4.5 kb immediately upstream of the wg transcription unit can direct expression of the reporter gene lacZ in domains similar to the normal wg pattern in the embryonic ectoderm. Expression of this reporter construct expands in ptc mutants and responds to hh activity. Within this 4.5 kb, a 150 bp element, highly conserved between D. melanogaster and Drosophila virilis, is required to spatially restrict wg transcription. Activity of this element depends on ptc, but it contains no consensus Ci-binding sites. The discovery of an element that is likely to bind a transcriptional repressor was unexpected, since the prevailing model suggests that wg expression is principally controlled by Hh signaling acting through the Ci activator. We show that wg regulatory DNA can drive lacZ in a proper wg-like pattern without any conserved Ci-binding sites and suggest that Ci can not be the sole endpoint of the Hh pathway.

scholarly journals Ventralization of the Drosophila embryo by deletion of extracellular leucine-rich repeats in the Toll protein.

1995 ◽  
Vol 6 (5) ◽  
pp. 587-596 ◽  
Author(s):  
K A Winans ◽  
C Hashimoto
Keyword(s):  
Cell Fate ◽  
Transmembrane Protein ◽  
Signal Transduction Pathway ◽  
Extracellular Domain ◽  
Drosophila Embryo ◽  
Transduction Pathway ◽  
Wild Type ◽  
Truncated Form ◽  
Biochemical Analyses ◽  
Leucine Rich Repeats

Dorsoventral polarity of the Drosophila embryo is established by a signal transduction pathway in which the maternal transmembrane protein Toll appears to function as the receptor for a ventrally localized extracellular ligand. Certain dominant Toll alleles encode proteins that behave as partially ligand-independent receptors, causing embryos containing these proteins to become ventralized. In extracts of embryos derived from mothers carrying these dominant alleles, we detected a polypeptide of approximately 35 kDa in addition to full-length Toll polypeptides with antibodies to Toll. Our biochemical analyses suggest that the smaller polypeptide is a truncated form of Toll lacking extracellular domain sequences. To assay the biological activity of such a shortened form of Toll, we synthesized RNA encoding a mutant polypeptide lacking the leucine-rich repeats that comprise most of Toll's extracellular domain and injected this RNA into embryos. The truncated Toll protein elicited the most ventral cell fate independently of the wild-type Toll protein and its ligand. These results support the view that Toll is a receptor whose extracellular domain regulates the intrinsic signaling activity of its cytoplasmic domain.

Evolutionary conservation of homeodomain-binding sites and other sequences upstream and within the major transcription unit of the Drosophila segmentation gene engrailed

1989 ◽  
Vol 9 (10) ◽  
pp. 4304-4311
Author(s):  
J A Kassis ◽  
C Desplan ◽  
D K Wright ◽  
P H O'Farrell
Keyword(s):  
Binding Sites ◽  
Regulatory Region ◽  
Divergence Time ◽  
Evolutionary Conservation ◽  
Transcription Unit ◽  
Regulatory Proteins ◽  
Coding Region ◽  
Cis Acting ◽  
Perfect Sequence ◽  
Development Proceeds

The engrailed (en) gene functions throughout Drosophila development and is expressed in a succession of intricate spatial patterns as development proceeds. Normal en function relies on an extremely large cis-acting regulatory region (70 kilobases). We are using evolutionary conservation to help identify en sequences important in regulating patterned expression. Sequence comparison of 2.6 kilobases upstream of the en coding region of D. melanogaster and D. virilis (estimated divergence time, 60 million years) showed that 30% of this DNA occurs in islands of near perfect sequence conservation. One of these conserved islands contains binding sites for homeodomain-containing proteins. It has been shown genetically that homeodomain-containing proteins regulate en expression. Our data suggested that this regulation may be direct. The remaining conserved islands may contain binding sites for other regulatory proteins.

scholarly journals Evolutionary conservation of homeodomain-binding sites and other sequences upstream and within the major transcription unit of the Drosophila segmentation gene engrailed.

1989 ◽  
Vol 9 (10) ◽  
pp. 4304-4311 ◽  
Author(s):  
J A Kassis ◽  
C Desplan ◽  
D K Wright ◽  
P H O'Farrell
Keyword(s):  
Binding Sites ◽  
Regulatory Region ◽  
Divergence Time ◽  
Evolutionary Conservation ◽  
Transcription Unit ◽  
Regulatory Proteins ◽  
Coding Region ◽  
Cis Acting ◽  
Perfect Sequence ◽  
Development Proceeds

The engrailed (en) gene functions throughout Drosophila development and is expressed in a succession of intricate spatial patterns as development proceeds. Normal en function relies on an extremely large cis-acting regulatory region (70 kilobases). We are using evolutionary conservation to help identify en sequences important in regulating patterned expression. Sequence comparison of 2.6 kilobases upstream of the en coding region of D. melanogaster and D. virilis (estimated divergence time, 60 million years) showed that 30% of this DNA occurs in islands of near perfect sequence conservation. One of these conserved islands contains binding sites for homeodomain-containing proteins. It has been shown genetically that homeodomain-containing proteins regulate en expression. Our data suggested that this regulation may be direct. The remaining conserved islands may contain binding sites for other regulatory proteins.

Genetic analysis of hedgehog signalling in the Drosophila embryo

Development ◽  
1993 ◽  
Vol 119 (Supplement) ◽  
pp. 115-124 ◽  
Author(s):  
A. J. Forbes ◽  
Y. Nakano ◽  
A. M. Taylor ◽  
P. W. Ingham
Keyword(s):  
Genetic Analysis ◽  
Transcriptional Activation ◽  
Secretory Pathway ◽  
Transcription Unit ◽  
Molecular Structures ◽  
Drosophila Embryo ◽  
Cubitus Interruptus ◽  
Cis Acting ◽  
Segment Polarity Genes ◽  
Segment Polarity

The segment polarity genes play a fundamental role in the patterning of cells within individual body segments of the Drosophila embryo. Two of these genes wingless (wg) and hedgehog (hh) encode proteins that enter the secretory pathway and both are thought to act by instructing the fates of cells neighbouring those in which they are expressed. Genetic analysis bas identified the transcriptional activation of wg as one of the targets of hh activity: here we present evidence that transduction of the hh-encoded signal is mediated by the activity of four other segment polarity genes, patched, fused, costal-2 and cubitus interruptus. The results of our genetic epistatsis analysis together with the molecular structures of the products of these genes where known, suggest a pathway of interactions leading from reception of the hh-encoded signal at the cell membrane to transcriptional activation in the cell nucleus. We have also found that transcription of patched is regulated by the same pathway and describe the identification of cis-acting upstream elements of the ptc transcription unit that mediate this regulation.

Molecular organization and embryonic expression of the hedgehog gene involved in cell-cell communication in segmental patterning of Drosophila

Development ◽  
1992 ◽  
Vol 115 (4) ◽  
pp. 957-971 ◽  
Author(s):  
J. Mohler ◽  
K. Vani
Keyword(s):  
Transmembrane Protein ◽  
Cell Communication ◽  
Protein Product ◽  
Drosophila Embryo ◽  
Molecular Organization ◽  
Posterior Portion ◽  
Segment Polarity ◽  
Segment Polarity Gene ◽  
Polarity Gene ◽  
Cell Cell

hedgehog is a segment polarity gene necessary to maintain the proper organization of each segment of the Drosophila embryo. We have identified the physical location of a number of rearrangement breakpoints associated with hedgehog mutations. The corresponding hh RNA is expressed in a series of segmental stripes starting at cellular blastoderm in the posterior portion of each segment. This RNA is localized predominantly within nuclei until stage 10, when the localization becomes primarily cytoplasmic. Expression of hh RNA in the posterior compartment is independent of most other segment polarity genes, including en, until the late extended germ-band stage (stage 11). Sequence analysis of the hedgehog locus suggests the protein product is a transmembrane protein, which may, therefore, be directly involved in cell-cell communication.

scholarly journals N-3-Hydroxy Dodecanoyl-DL-homoserine Lactone (OH-dDHL) Triggers Apoptosis of Bone Marrow-Derived Macrophages through the ER- and Mitochondria-Mediated Pathways

2021 ◽  
Vol 22 (14) ◽  
pp. 7565
Author(s):  
Kyungho Woo ◽  
Dong Ho Kim ◽  
Man Hwan Oh ◽  
Ho Sung Park ◽  
Chul Hee Choi
Keyword(s):  
Bone Marrow ◽  
Quorum Sensing ◽  
Deletion Mutant ◽  
Transmembrane Protein ◽  
Cell Communication ◽  
Homoserine Lactone ◽  
Host Responses ◽  
Wild Type ◽  
Mutant Strains

Quorum sensing of Acinetobacter nosocomialis for cell-to-cell communication produces N-3-hydroxy dodecanoyl-DL-homoserine lactone (OH-dDHL) by an AnoR/I two-component system. However, OH-dDHL-driven apoptotic mechanisms in hosts have not been clearly defined. Here, we investigated the induction of apoptosis signaling pathways in bone marrow-derived macrophages treated with synthetic OH-dDHL. Moreover, the quorum-sensing system for virulence regulation was evaluated in vivo using wild-type and anoI-deletion mutant strains. OH-dDHL decreased the viability of macrophage and epithelial cells in dose- and time-dependent manners. OH-dDHL induced Ca2+ efflux and caspase-12 activation by ER stress transmembrane protein (IRE1 and ATF6a p50) aggregation and induced mitochondrial dysfunction through reactive oxygen species (ROS) production, which caused cytochrome c to leak. Pretreatment with a pan-caspase inhibitor reduced caspase-3, -8, and -9, which were activated by OH-dDHL. Pro-inflammatory cytokine and paraoxonase-2 (PON2) gene expression were increased by OH-dDHL. We showed that the anoI-deletion mutant strains have less intracellular invasion compared to the wild-type strain, and their virulence, such as colonization and dissemination, was decreased in vivo. Consequently, these findings revealed that OH-dDHL, as a virulence factor, contributes to bacterial infection and survival as well as the modification of host responses in the early stages of infection.

Determination of spatial domains of zygotic gene expression in the Drosophila embryo by the affinity of binding sites for the bicoid morphogen

Nature ◽  
1989 ◽  
Vol 340 (6232) ◽  
pp. 363-367 ◽  
Author(s):  
Wolfgang Driever ◽  
Gudrun Thoma ◽  
Christiane Nüsslein-Volhard
Keyword(s):  
Gene Expression ◽  
Binding Sites ◽  
Drosophila Embryo ◽  
Zygotic Gene ◽  
Spatial Domains

Probing Drosophila gene function by antisense RNA

Genome ◽  
1989 ◽  
Vol 31 (1) ◽  
pp. 422-425 ◽  
Author(s):  
Reinhard Schuh ◽  
Herbert Jäckle
Keyword(s):  
Antisense Rna ◽  
Germ Line ◽  
Conventional Technique ◽  
Transcription Unit ◽  
The Body ◽  
Mutant Phenotype ◽  
Drosophila Embryo ◽  
Alternative Approach ◽  
Pattern Forming ◽  
Germ Line Transformation

The conventional technique for assigning a particular genetic function to a cloned transcription unit has relied on the rescue of the mutant phenotype by germ line transformation. An alternative approach is to mimic a mutant phenotype by the use of antisense RNA injections to produce phenocopies. This approach has been successfully used to identify genes involved in early pattern forming processes in the Drosophila embryo. At the time when antisense RNA is injected, the embryo develops as a syncytium composed of about 5000 nuclei which share a common cytoplasm. The gene interactions required to establish the body plan occur before cellularization at the blastoderm stage. Thus the nuclei and their exported transcripts are accessible to the injected antisense RNA. The antisense RNA interferes with the endogenous RNA by an as yet unidentified mechanism. The extent of interference is only partial and produces phenocopies with characteristics of weak mutant alleles. In our lab and others, this approach has been successfully used to identify several genes required for normal Drosophila pattern formation.Key words: Drosophila segmentation, phenocopy, antisense RNA, Krüppel gene.

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