The Drosophila E74 gene is required for metamorphosis and plays a role in the polytene chromosome puffing response to ecdysone

Development ◽  
1995 ◽  
Vol 121 (5) ◽  
pp. 1455-1465 ◽  
Author(s):  
J.C. Fletcher ◽  
K.C. Burtis ◽  
D.S. Hogness ◽  
C.S. Thummel
Keyword(s):  
Gene Expression ◽  
Salivary Gland ◽  
Critical Role ◽  
Polytene Chromosomes ◽  
Transcription Unit ◽  
Loss Of Function ◽  
Phenotypic Analysis ◽  
Pupal Development ◽  
Puparium Formation ◽  
Early Puff

The steroid hormone ecdysone initiates Drosophila metamorphosis by reprogramming gene expression during late larval and prepupal development. The ecdysone-inducible gene E74, a member of the ets proto-oncogene family, has been proposed to play a key role in this process. E74 is encoded within the 74EF early puff and consists of two overlapping transcription units, E74A and E74B. To assess the function(s) of E74 during metamorphosis, we have isolated and characterized recessive loss-of-function mutations specific to each transcription unit. We find that mutations in E74A and E74B are predominantly lethal during prepupal and pupal development, consistent with a critical role for their gene products in metamorphosis. Phenotypic analysis reveals that E74 function is required for both pupariation and pupation, and for the metamorphosis of both larval and imaginal tissues. E74B mutants are defective in puparium formation and head eversion and die as prepupae or cryptocephalic pupae, while E74A mutants pupariate normally and die either as prepupae or pharate adults. We have also investigated the effects of the E74 mutations on gene expression by examining the puffing pattern of the salivary gland polytene chromosomes in newly formed mutant prepupae. Most puffs are only modestly affected by the E74B mutation, whereas a subset of late puffs are sub-maximally induced in E74A mutant prepupae. These observations are consistent with Ashburner's proposal that early puff proteins induce the formation of late puffs, and define E74A as a regulator of late puff activity. They also demonstrate that E74 plays a wide role in reshaping the insect during metamorphosis, affecting tissues other than the salivary gland in which it was originally identified.

Genetic Analysis of the Drosophila 63F Early Puff: Characterization of Mutations in E63-1 and maggie, a Putative Tom22

Genetics ◽  
2000 ◽  
Vol 156 (1) ◽  
pp. 229-244
Author(s):  
Martina Vaskova ◽  
A M Bentley ◽  
Samantha Marshall ◽  
Pamela Reid ◽  
Carl S Thummel ◽  
...  
Keyword(s):  
Salivary Gland ◽  
Genetic Analysis ◽  
Polytene Chromosomes ◽  
Reading Frame ◽  
Protein Levels ◽  
Ef Hand ◽  
Larval Salivary Gland ◽  
Complementation Groups ◽  
Inducible Genes ◽  
Early Puff

Abstract The 63F early puff in the larval salivary gland polytene chromosomes contains the divergently transcribed E63-1 and E63-2 ecdysone-inducible genes. E63-1 encodes a member of the EF-hand family of Ca2+-binding proteins, while E63-2 has no apparent open reading frame. To understand the functions of the E63 genes, we have determined the temporal and spatial patterns of E63-1 protein expression, as well as undertaken a genetic analysis of the 63F puff. We show that E63-1 is expressed in many embryonic and larval tissues, but the third-instar larval salivary gland is the only tissue where increases in protein levels correlate with increases in ecdysone titer. Furthermore, the subcellular distribution of E63-1 protein changes dynamically in the salivary glands at the onset of metamorphosis. E63-1 and E63-2 null mutations, however, have no effect on development or fertility. We have characterized 40 kb of the 63F region, defined as the interval between Ubi-p and E63-2, and have identified three lethal complementation groups that correspond to the dSc-2, ida, and mge genes. We show that mge mutations lead to first-instar larval lethality and that Mge protein is similar to the Tom22 mitochondrial import proteins of fungi, suggesting that it has a role in mitochondrial function.

Zebrafish hox genes: expression in the hindbrain region of wild-type and mutants of the segmentation gene, valentino

Development ◽  
1998 ◽  
Vol 125 (3) ◽  
pp. 393-406 ◽  
Author(s):  
V.E. Prince ◽  
C.B. Moens ◽  
C.B. Kimmel ◽  
R.K. Ho
Keyword(s):  
Gene Expression ◽  
Gene Product ◽  
Hox Genes ◽  
Developmental Stages ◽  
Expression Profiles ◽  
Critical Role ◽  
Loss Of Function ◽  
Hox Gene ◽  
Segmentation Gene ◽  
Functional Changes

The developing hindbrain is organized into a series of segments termed rhombomeres which represent lineage restricted compartments correlating with domains of gene expression and neuronal differentiation. In this study, we investigate the processes of hindbrain segmentation and the acquisition of segmental identity by analyzing the expression of zebrafish hox genes in the hindbrains of normal fish and fish with a loss-of-function mutation in the segmentation gene valentino (val, the homologue of mouse kreisler; Moens, C. B., Cordes, S. P. Giorgianni, M. W., Barsh, G. S. and Kimmel, C. B. (1998). Development 125, 381–391). We find that zebrafish hox genes generally have similar expression profiles to their murine and avian counterparts, although there are several differences in timing and spatial extent of expression which may underlie some of the functional changes that have occurred along the separate evolutionary lineages of teleosts and tetrapods. Our analysis of hox gene expression in val- embryos confirms that the val gene product is important for subdivision of the presumptive rhombomere 5 and 6 territory into definitive rhombomeres, suggests that the val gene product plays a critical role in regulating hox gene transcription, and indicates that some neural crest cells are inappropriately specified in val- embryos. Our analysis of gene expression at several developmental stages has allowed us to infer differences between primary and secondary defects in the val mutant: we find that extended domains of expression for some hox genes are secondary, late phenomena potentially resulting from inappropriate cell mixing or lack of normal inter-rhombomeric interactions in the caudal hindbrain.

scholarly journals Osteoarthritic Subchondral Bone Release Exosomes That Promote Cartilage Degeneration

Cells ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 251
Author(s):  
Xiaoxin Wu ◽  
Ross Crawford ◽  
Yin Xiao ◽  
Xinzhan Mao ◽  
Indira Prasadam
Keyword(s):  
Gene Expression ◽  
Articular Cartilage ◽  
Rna Sequencing ◽  
Subchondral Bone ◽  
Critical Role ◽  
Cartilage Degeneration ◽  
Marker Genes ◽  
Specific Marker ◽  
Catabolic Gene ◽  
Loss Of Function

Altered subchondral bone and articular cartilage interactions have been implicated in the pathogenesis of osteoarthritis (OA); however, the mechanisms remain unknown. Exosomes are membrane-derived vesicles that have recently been recognized as important mediators of intercellular communication. Herein, we investigated if OA subchondral bone derived exosomes alter transcriptional and bioenergetic signatures of chondrocytes. Exosomes were isolated and purified from osteoblasts of nonsclerotic or sclerotic zones of human OA subchondral bone and their role on the articular cartilage chondrocytes was evaluated by measuring the extent of extracellular matrix production, cellular bioenergetics, and the expression of chondrocyte activity associated marker genes. Exosomal microRNAs were analyzed using RNA sequencing and validated by quantitative real-time PCR and loss-of-function. In coculture studies, chondrocytes internalized OA sclerotic subchondral bone osteoblast derived exosomes and triggered catabolic gene expression and reduced chondrocyte-specific marker expression a phenomenon that is often observed in OA cartilage. RNA sequencing and miRNA profiling have identified miR-210-5p, which is highly enriched in OA sclerotic subchondral bone osteoblast exosomes, triggered the catabolic gene expression in articular cartilage chondrocytes. Importantly, we demonstrate that miR-210-5p suppresses the oxygen consumption rate of chondrocytes, altering their bioenergetic state that is often observed in OA conditions. These effects were markedly inhibited by the addition of a miR-210-5p inhibitor. Our study indicates that exosomes released by OA sclerotic subchondral bone osteoblasts plays a critical role in progression of cartilage degeneration and might be a potential target for therapeutic intervention in OA.

scholarly journals A Raf-like kinase is required for smoke-induced seed dormancy in Arabidopsis thaliana

2021 ◽  
Vol 118 (14) ◽  
pp. e2020636118
Author(s):  
Inhye Lee ◽  
Eunsun Kim ◽  
Soobin Choi ◽  
Dayoung Kim ◽  
Wangyu Hong ◽  
...  
Keyword(s):  
Gene Expression ◽  
Arabidopsis Thaliana ◽  
Seed Germination ◽  
Seed Dormancy ◽  
Higher Plants ◽  
Critical Role ◽  
Phenotypic Analysis ◽  
Genetic Components ◽  
Dependent Inhibition ◽  
Molecular Aspects

Plants sense and integrate diverse stimuli to determine the timing for germination. A smoke compound, 3,4,5-trimethylfuran-2(5H)-one (trimethylbutenolide, TMB), has been identified to inhibit the seed germination of higher plants. To understand the mode of action, we examined various physiological and molecular aspects of the TMB-dependent inhibition of seed germination in Arabidopsis thaliana. The results indicated that the effect of TMB is due to the enhanced physiological dormancy, which is modulated by other dormancy regulatory cues such as after-ripening, stratification, and ABA/GA signaling. In addition, gene expression profiling showed that TMB caused genome-wide transcriptional changes, altering the expression of a series of dormancy-related genes. Based on the TMB-responsive physiological contexts in Arabidopsis, we performed mutant screening to isolate genetic components that underpin the TMB-induced seed dormancy. As a result, the TMB-RESISTANT1 (TES1) gene in Arabidopsis, encoding a B2 group Raf-like kinase, was identified. Phenotypic analysis of the tes1 mutant implicated that TES1 has a critical role in the TMB-responsive gene expression and the inhibition of seed germination. Taken together, we propose that plants have been equipped with a TMB sensory pathway through which the TMB induces the seed dormancy in a TES1-dependent way.

STAT3 activation through IL-6/IL-11 in cancer-associated fibroblasts promotes colorectal tumour development and correlates with poor prognosis

Gut ◽  
2019 ◽  
Vol 69 (7) ◽  
pp. 1269-1282 ◽  
Author(s):  
Christina Heichler ◽  
Kristina Scheibe ◽  
Anabel Schmied ◽  
Carol I Geppert ◽  
Benjamin Schmid ◽  
...  
Keyword(s):  
Gene Expression ◽  
Colon Cancer ◽  
Gene Expression Profiling ◽  
Expression Profiling ◽  
Tumour Growth ◽  
Critical Role ◽  
Cancer Associated Fibroblasts ◽  
Loss Of Function ◽  
Colorectal Tumour

ObjectiveCancer-associated fibroblasts (CAFs) influence the tumour microenvironment and tumour growth. However, the role of CAFs in colorectal cancer (CRC) development is incompletely understood.DesignWe quantified phosphorylation of STAT3 (pSTAT3) expression in CAFs of human colon cancer tissue using a tissue microarray (TMA) of 375 patients, immunofluorescence staining and digital pathology. To investigate the functional role of CAFs in CRC, we took advantage of two murine models of colorectal neoplasia and advanced imaging technologies. In loss-of-function and gain-of-function experiments, using genetically modified mice with collagen type VI (COLVI)-specific signal transducer and activator of transcription 3 (STAT3) targeting, we evaluated STAT3 signalling in fibroblasts during colorectal tumour development. We performed a comparative gene expression profiling by whole genome RNA-sequencing of fibroblast subpopulations (COLVI+ vs COLVI–) on STAT3 activation (IL-6 vs IL-11).ResultsThe analysis of pSTAT3 expression in CAFs of human TMAs revealed a negative correlation of increased stromal pSTAT3 expression with the survival of colon cancer patients. In the loss-of-function and gain-of-function approach, we found a critical role of STAT3 activation in fibroblasts in driving colorectal tumourigenesis in vivo. With different imaging technologies, we detected an expansion of activated fibroblasts in colorectal neoplasias. Comparative gene expression profiling of fibroblast subpopulations on STAT3 activation revealed the regulation of transcriptional patterns associated with angiogenesis. Finally, the blockade of proangiogenic signalling significantly reduced colorectal tumour growth in mice with constitutive STAT3 activation in COLVI+ fibroblasts.ConclusionAltogether our work demonstrates a critical role of STAT3 activation in CAFs in CRC development.

The Drosophila E74 gene is required for the proper stage- and tissue-specific transcription of ecdysone-regulated genes at the onset of metamorphosis

Development ◽  
1995 ◽  
Vol 121 (5) ◽  
pp. 1411-1421 ◽  
Author(s):  
J.C. Fletcher ◽  
C.S. Thummel
Keyword(s):  
Salivary Gland ◽  
Critical Role ◽  
Polytene Chromosomes ◽  
Early Gene ◽  
Secondary Response ◽  
Phenotypic Characterization ◽  
Large Set ◽  
Late Genes ◽  
Larval Salivary Gland ◽  
Maximal Induction

The steroid hormone ecdysone directly induces a small set of early genes, visible as puffs in the larval salivary gland polytene chromosomes, as it signals the onset of Drosophila metamorphorsis. The products of these genes appear to function as regulators that both repress their own expression and induce a large set of secondary-response late genes. We have identified recessive loss-of-function mutations in the early gene E74, a member of the ets protooncogene family that encodes two related DNA-binding proteins, E74A and E74B. These mutations cause defects in pupariation and pupation, and result in lethality during metamorphosis. Here we extend our phenotypic characterization of the E74A and E74B mutant alleles to the molecular level by examining their effects on the transcription of over 30 ecdysone-regulated genes. We show that the transcription of most ecdysone primary-response genes during late larval and prepupal development is unaffected by the E74 mutations. Rather, we find that E74 is necessary for the appropriate regulation of many ecdysone secondary-response genes. E74B is required for the maximal induction of glue genes in mid third instar larval salivary glands, while E74A is required in early prepupae for the proper timing and maximal induction of a subset of late genes. E74 activity is also necessary for the correct regulation of genes expressed predominantly in the fat body, epidermis or imaginal discs. These observations confirm that E74 plays a critical role in regulating transcription during the early stages of Drosophila metamorphosis. In addition, the widespread effects of the E74 mutations on transcription indicate that E74 functions in regulatory hierarchies not only in the larval salivary gland, but throughout the entire organism.

LARVAL AGE AND THE PATTERN OF DNA SYNTHESIS IN POLYTENE CHROMOSOMES

1968 ◽  
Vol 10 (1) ◽  
pp. 82-90 ◽  
Author(s):  
David Nash ◽  
John Bell
Keyword(s):  
Drosophila Melanogaster ◽  
Salivary Gland ◽  
Dna Synthesis ◽  
Polytene Chromosomes ◽  
Larval Life ◽  
Gland Cells ◽  
Salivary Gland Cells ◽  
Puparium Formation ◽  
Chromosome Ii ◽  
Replicative Cycle

It has been shown, by autoradiography using H3-thymidine, that the frequency of salivary gland cells where DNA synthesis covers the entire length of a specific polytene chromosomal segment (Chromosome II, 56F-60A, Drosophila melanogaster) drops off some time during the last day of larval life. The frequency of highly discontinuous DNA synthesis over the same region remains at about the same level until a stage closer to puparium formation, when all DNA synthesis stops.If a cycle of DNA synthesis, once initiated, goes to completion, then this finding indicates that the patterns of spatially continuous synthesis tend to occur early in the replicative cycle and that the terminal phases of the cycle involve highly discontinuous patterns of synthesis.

The Drosophila 63F early puff contains E63-1, an ecdysone-inducible gene that encodes a novel Ca(2+)-binding protein

Development ◽  
1995 ◽  
Vol 121 (8) ◽  
pp. 2667-2679 ◽  
Author(s):  
A.J. Andres ◽  
C.S. Thummel
Keyword(s):  
Salivary Gland ◽  
Binding Protein ◽  
Polytene Chromosomes ◽  
Primary Response ◽  
Second Messenger Signaling ◽  
Additional Level ◽  
Inducible Genes ◽  
Early Puff ◽  
Inducible Gene

Pulses of ecdysone at the end of Drosophila larval development dramatically reprogram gene expression as they signal the onset of metamorphosis. Ecdysone directly induces several early puffs in the salivary gland polytene chromosomes that, in turn, activate many late puffs. Three early puffs, at 2B5, 74EF, and 75B, have been studied at the molecular level. Each contains a single ecdysone primary-response gene that encodes a family of widely expressed transcription factors. We report here a molecular characterization of the 63F early puff. Unexpectedly, we have found this locus to be significantly different from the previously characterized early puff loci. First, the 63F puff contains a pair of ecdysone-inducible genes that are transcribed in the larval salivary glands: E63-1 and E63-2. Second, E63-1 induction in late third instar larvae appears to be highly tissue-specific, restricted to the salivary gland. Third, E63-1 encodes a novel Ca(2+)-binding protein related to calmodulin. The discovery of an ecdysone-inducible Ca(2+)-binding protein provides a foundation for integrating steroid hormone and calcium second messenger signaling pathways and generates an additional level for potential regulation of the ecdysone response.

Patterns of puffing activity in the salivary gland polytene chromosomes of the medfly Ceratitis capitata, during larval and prepupal development

Genome ◽  
1999 ◽  
Vol 42 (5) ◽  
pp. 919-929 ◽  
Author(s):  
Angeliki Gariou-Papalexiou ◽  
George Chrysanthis ◽  
Anastassios C Mintzas ◽  
Antigone Zacharopoulou
Keyword(s):  
Salivary Gland ◽  
Larval Stage ◽  
Ceratitis Capitata ◽  
Polytene Chromosomes ◽  
Group Iv ◽  
Developmental Period ◽  
Positive Correlation ◽  
Puparium Formation

The patterns of puffing activity in the salivary gland polytene chromosomes have been studied during the late larval and prepupal stages of the medfly Ceratitis capitata. A total of 128 loci, with significant changes in puffing activity during this developmental period, were assigned to the five autosomes of the medfly. Two waves of puffing activity were observed, the first during the late larval stage and the second during the prepupal development. Overall puffing activity can be divided into four groups, group-IV activity being most conspicuous with 58 active loci. The major changes in puffing activity take place around jumping, a characteristic event occurring about 6 h before puparium formation, at puparium formation, and during midprepupal development. The overall puffing activity shows a positive correlation to the ecdysone titer in the hemolymph, suggesting that most of the changes in the activity of the puffs during the late larval and prepupal stages of the medfly may be regulated by ecdysone.Key words: polytene chromosomes, puffing patterns, ecdysone, Ceratitis capitata.

ALTERED STEROID INDUCED PUFFING BY CHROMATIN BOUND ALUMINUM IN A POLYTENE CHROMOSOME OF THE BLACKFLY SIMULIUM VITTATUM

1982 ◽  
Vol 24 (1) ◽  
pp. 27-36 ◽  
Author(s):  
Catherine L. Sanderson ◽  
Donald R. Crapper McLachlan ◽  
Umberto De Boni
Keyword(s):  
Gene Expression ◽  
Salivary Gland ◽  
Polytene Chromosomes ◽  
Cell Types ◽  
Toxic Action ◽  
Nuclear Chromatin ◽  
Experimental Animals ◽  
Simulium Vittatum ◽  
Salivary Gland Cells

The neurotoxic element aluminum accumulates selectively upon nuclear chromatin of several cell types, including neurons and glial cells of experimental animals and man. However, no mechanism of toxic action has been identified. Histometric analyses of the puffing patterns induced by ecdysterone in polytene chromosomes in the dipteran, Simulium vittatum (Zetterstedt) showed that chromosomes of salivary gland cells exposed to aluminum in vitro exhibit significant alterations in their response to ecdysterone. Specifically, chromatin bound aluminum completely inhibits (p < 0.05) puffing at seven out of nine sites normally puffed by ecdysterone and partially inhibits (p < 0.05) puffing at one site. Aluminum induces a partial puff (p < 0.05) at one site previously inhibited when both aluminum and ecdysterone were present. These findings suggest that one mode of toxic action of chromatin bound aluminum may be related to changes in gene expression.

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