Roles of wingless in patterning the larval epidermis of Drosophila

Development ◽  
1991 ◽  
Vol 113 (2) ◽  
pp. 471-485 ◽  
Author(s):  
A. Bejsovec ◽  
A. Martinez Arias
Keyword(s):  
Gene Product ◽  
Epidermal Cells ◽  
Stable Expression ◽  
Gene Products ◽  
Anterior Portion ◽  
Posterior Portion ◽  
Present Evidence ◽  
Larval Cuticle ◽  
Cuticular Structures

The larval epidermis of Drosophila shows a stereotyped segmentally repeating pattern of cuticular structures. Mutants deficient for the wingless gene product show highly disrupted patterning of the larval cuticle. We have manipulated expression of the wg gene product to assess its role in this patterning process. We present evidence for four distinct phases of wg function in epidermal cells: (1) an early requirement in engrailed-expressing cells to establish and maintain stable expression of en, (2) a discrete period when wg and en gene products act in concert to generate positional values in the anterior portion of the ventral segment and all values of the dorsal and lateral epidermis, (3) a progressive function (dependent on prior interaction with the en-expressing cells) in conferring positional values to cells within the posterior portion of the segment, and (4) a late continuous requirement for maintaining some ventral positional values.

The roles of hedgehog and engrailed in patterning adult abdominal segments of Drosophila

Development ◽  
1997 ◽  
Vol 124 (19) ◽  
pp. 3703-3714 ◽  
Author(s):  
A. Kopp ◽  
M.A. Muskavitch ◽  
I. Duncan
Keyword(s):  
Ectopic Expression ◽  
Restrictive Temperature ◽  
Primary Role ◽  
Loss Of Function ◽  
Posterior Compartment ◽  
Anterior Portion ◽  
Posterior Portion ◽  
Anterior Compartment ◽  
Present Evidence ◽  
Anterior Patterning

We present evidence that hedgehog (hh) protein secreted by posterior compartment cells plays a key role in patterning the posterior portion of the anterior compartment in adult abdominal segments. Loss of function of hh in the hh(ts2) mutant causes the loss of posterior tergite characteristics in the anterior compartment, whereas ectopic expression driven by hs-hh or the gain-of-function allele hh(Mir) causes transformation of anterior structures toward the posterior. FLP-out hh-expressing clones in the anterior compartment induce surrounding wild-type cells to produce posterior tergite structures, establishing that hh functions nonautonomously. The effects of pulses of ectopic expression driven by hs-hh indicate that bristle type and pigmentation are patterned by hh at widely different times in pupal development. We also present evidence that the primary polarization of abdominal segments is symmetric. This symmetry is strikingly revealed by ectopic expression of engrailed (en). As expected, this transforms anterior compartment cells to posterior compartment identity. In addition, however, ectopic en expression causes an autonomous reversal of polarity in the anterior portion of the anterior compartment, but not the posterior portion. By determining the position of polarity reversal within en-expressing clones, we were able to define a cryptic line of symmetry that lies within the pigment band of the normal tergite. This line appears to be retained in hh(ts2) mutants raised at the restrictive temperature, suggesting it is not established by hh signaling. We argue that the primary role of hh in controlling polarity is to cause anterior compartment cells to reverse their interpretation of an underlying symmetric polarization. Consistent with this, we find that strong ectopic expression of hh causes mirror-symmetric double posterior patterning, whereas hh loss of function can cause mirror-symmetric double anterior patterning.

The tricornered Gene, Which Is Required for the Integrity of Epidermal Cell Extensions, Encodes the Drosophila Nuclear DBF2-Related Kinase

Genetics ◽  
2000 ◽  
Vol 156 (4) ◽  
pp. 1817-1828 ◽  
Author(s):  
Wei Geng ◽  
Biao He ◽  
Mina Wang ◽  
Paul N Adler
Keyword(s):  
Actin Cytoskeleton ◽  
Actin Polymerization ◽  
Cell Structure ◽  
Cytochalasin D ◽  
Epidermal Cells ◽  
Sense Organs ◽  
Latrunculin A ◽  
Cellular Extensions ◽  
Cuticular Structures ◽  
Cuticular Surface

Abstract During their differentiation epidermal cells of Drosophila form a rich variety of polarized structures. These include the epidermal hairs that decorate much of the adult cuticular surface, the shafts of the bristle sense organs, the lateral extensions of the arista, and the larval denticles. These cuticular structures are produced by cytoskeletal-mediated outgrowths of epidermal cells. Mutations in the tricornered gene result in the splitting or branching of all of these structures. Thus, tricornered function appears to be important for maintaining the integrity of the outgrowths. tricornered mutations however do not have major effects on the growth or shape of these cellular extensions. Inhibiting actin polymerization in differentiating cells by cytochalasin D or latrunculin A treatment also induces the splitting of hairs and bristles, suggesting that the actin cytoskeleton might be a target of tricornered. However, the drugs also result in short, fat, and occasionally malformed hairs and bristles. The data suggest that the function of the actin cytoskeleton is important for maintaining the integrity of cellular extensions as well as their growth and shape. Thus, if tricornered causes the splitting of cellular extensions by interacting with the actin cytoskeleton it likely does so in a subtle way. Consistent with this possibility we found that a weak tricornered mutant is hypersensitive to cytochalasin D. We have cloned the tricornered gene and found that it encodes the Drosophila NDR kinase. This is a conserved ser/thr protein kinase found in Caenorhabditis elegans and humans that is related to a number of kinases that have been found to be important in controlling cell structure and proliferation.

scholarly journals The immunosuppressant SR 31747 blocks cell proliferation by inhibiting a steroid isomerase in Saccharomyces cerevisiae.

1996 ◽  
Vol 16 (6) ◽  
pp. 2719-2727 ◽  
Author(s):  
S Silve ◽  
P Leplatois ◽  
A Josse ◽  
P H Dupuy ◽  
C Lanau ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Cell Proliferation ◽  
Gene Product ◽  
In Vitro Assays ◽  
Gene Products ◽  
Yeast Saccharomyces Cerevisiae ◽  
Isomerase Activity ◽  
Encoding Gene ◽  
Resistant Mutants

SR 31747 is a novel immunosuppressant agent that arrests cell proliferation in the yeast Saccharomyces cerevisiae, SR 31747-treated cells accumulate the same aberrant sterols as those found in a mutant impaired in delta 8- delta 7-sterol isomerase. Sterol isomerase activity is also inhibited by SR 31747 in in vitro assays. Overexpression of the sterol isomerase-encoding gene, ERG2, confers enhanced SR resistance. Cells growing anaerobically on ergosterol-containing medium are not sensitive to SR. Disruption of the sterol isomerase-encoding gene is lethal in cells growing in the absence of exogenous ergosterol, except in SR-resistant mutants lacking either the SUR4 or the FEN1 gene product. The results suggest that sterol isomerase is the target of SR 31747 and that both the SUR4 and FEN1 gene products are required to mediate the proliferation arrest induced by ergosterol depletion.

Deletions in the C-terminal coding region of the v-sis gene: dimerization is required for transformation

1986 ◽  
Vol 6 (4) ◽  
pp. 1304-1314
Author(s):  
M Hannink ◽  
M K Sauer ◽  
D J Donoghue
Keyword(s):  
Growth Factor ◽  
Gene Product ◽  
Platelet Derived Growth Factor ◽  
Deletion Mutants ◽  
Gene Products ◽  
Coding Region ◽  
Strong Connection ◽  
C Terminus ◽  
Its Gene ◽  
Transforming Gene

The v-sis gene encodes chain B of platelet-derived growth factor. However, this gene codes for additional amino acids at both the N terminus and the C terminus of its gene product which are not present in the amino acid sequence of platelet-derived growth factor. We constructed a series of deletion mutants with deletions in the v-sis gene in order to define the C-terminal limit of the v-sis gene product which is required for transformation. Deletion mutants of the v-sis gene which encoded truncated gene products up to 57 residues shorter than the v-siswt gene product were still able to transform cells. The minimal transforming region of the v-sis gene product contained six residues fewer than were present in chain B of platelet-derived growth factor. Only 10 residues, including the sequence Cys-Lys-Cys, separated the smallest transforming gene product from the largest nontransforming gene product. These cysteine residues were also important for dimerization of the v-sis gene product, since all of the nontransforming v-sis deletions were unable to form dimers when they were analyzed under nonreducing conditions. Our results suggest that there is a strong connection between transformation and dimerization.

The Drosophila dCREB-A gene is required for dorsal/ventral patterning of the larval cuticle

Development ◽  
1997 ◽  
Vol 124 (1) ◽  
pp. 181-193 ◽  
Author(s):  
D.J. Andrew ◽  
A. Baig ◽  
P. Bhanot ◽  
S.M. Smolik ◽  
K.D. Henderson
Keyword(s):  
Gene Expression ◽  
Transcription Factor ◽  
Signaling Cascades ◽  
Loss Of Function ◽  
Larval Cuticle ◽  
Extracellular Signals ◽  
Patterning Genes ◽  
Lateral Structures ◽  
Cuticular Structures

We report on the characterization of the first loss-of-function mutation in a Drosophila CREB gene, dCREB-A. In the epidermis, dCREB-A is required for patterning cuticular structures on both dorsal and ventral surfaces since dCREB-A mutant larvae have only lateral structures around the entire circumference of each segment. Based on results from epistasis tests with known dorsal/ventral patterning genes, we propose that dCREB-A encodes a transcription factor that functions near the end of both the DPP- and SPI-signaling cascades to translate the corresponding extracellular signals into changes in gene expression. The lateralizing phenotype of dCREB-A mutants reveals a much broader function for CREB proteins than previously thought.

Computed Tomogram Findings of Mucous Recirculation between the Natural and Accessory Ostia of the Maxillary Sinus

2002 ◽  
Vol 16 (5) ◽  
pp. 265-268 ◽  
Author(s):  
Seung-Kyu Chung ◽  
Do Yeon Cho ◽  
Hun Jong Dhong
Keyword(s):  
Maxillary Sinus ◽  
Ring Structure ◽  
Endoscopic Examination ◽  
Mucous Secretion ◽  
Middle Portion ◽  
Anterior Portion ◽  
Posterior Portion

Background The phenomenon of recirculation involves the circulation of mucous secretion between the natural ostium and other openings and is observed mainly after surgery when the surgical opening is not connected. Methods Seven patients with a mucous stream transporting into an accessory ostium, as found during endoscopic examination, were entered into study. The coronal computed tomogram findings of the mucous recirculation were analyzed at three levels: anterior, middle, and posterior portion of it. Results The anterior portion was visualized at the level of the natural ostium in five patients. The middle portion inside the maxillary sinus was visible in six cases. The posterior portion was visualized at the level of the accessory ostium in five patients. Among the axial scans, mucous rings were visible in two patients. Conclusions The primary mucous recirculation between the natural and accessory openings is shown as a ring structure in coronal computed tomogram scans.

Memoirs: The Chondrocranium of Calotes versicolor (Daud.) with a Desription of the Osteocranium of a just-hatched Young

1946 ◽  
Vol s2-87 (347) ◽  
pp. 237-297
Author(s):  
L. S. RAMASWAMI
Keyword(s):  
Ventral Side ◽  
Otic Capsule ◽  
Anterior Portion ◽  
Posterior Portion ◽  
Early Stages ◽  
Median Part ◽  
Dorsal Portion ◽  
Calotes Versicolor ◽  
Anterior Semicircular Canal ◽  
Atlas And Axis

1. In the earliest stage of Calotes studied, the basal plate is confluent with the pleurocentrum of the atlas and axis vertebrae. Later, a joint appears between the hypocentral condyle and the first vertebra. This shows that, at least temporarily, the elements of the anterior sclerotomic half in this region are in continuity with the posterior in front as happens in the vertebral region. The occipito-atlantic joint is, therefore, intravertebral and intersegmental as in other Lacertilia. 2. The anterior semicircular canal is completely separated for a short distance from the remaining otic capsule. The gap is filled with connective tissue. 3. The intervestibular septum shows a lateral foramen which transmits nothing and the utricular connexion between the anterior and posterior chambers passes posteriorly to the median part of the septum and, therefore, a medial orifice is not formed. 4. The preoptic roots, the orbital cartilages, and metoptic pila are paired in early stages; the orbital cartilage connects the preoptic root, pila metoptica and pila antotica dorsally. Later the two preoptic roots merge to form a median preoptic pillar, the orbital cartilages anteriorly unite to form the planum supraseptale, while posteriorly also the orbital cartilages (taenia medialis) unite at the region of the hypophysial foramen. This posterior united portion is met by a median vertical pillar (formed by the fusion of cartilago hypochiasmatica, subiculum infundibuli, and pilae metopticae) arising from the trabecula communis. The single septal fenestra is divided into an anterior larger and a posterior optic by the formation of median interorbital pillar from the ventral interorbital septum which meets the posterior portion of the planum supraseptale. The ventral portion of the interorbital septum is never noticed to be paired; the taenia marginalis is absent. However, short projections from the posterodorsal margin of the planum and from the anterodorsal face of the otic capsule represent the reminiscence of marginalis connexion. A supratrabecular bar is absent. 5. In the nasal capsule, a concha nasalis is absent; therefore, the lateral nasal glands are unenclosed in a cartilaginous capsule. The anterior portion of the paranasal cartilage unites with the dorsal portion of the lamina transversalis anterior, and the latter gives rise to an ectochoanal cartilage, but a paraseptal cartilage is absent. On the ventral side, from the free median margin of the lamina orbitonasalis, there arises a short projection which represents the posterior portion of the paraseptal cartilage. 6. The pterygoquadrate shows a free streptostylic quadrate, a processus ascendens which ossifies into the epipterygoid, a processus pterygoideus only in early stages, a basipterygoid articulation by a free meniscus cartilage, and an otic articulation with the crista parotica and processus paroticus by the quadrate. 7. The columella auris shows a ligamentary processus dorsalis connexion with the processus paroticus, a cartilaginous processus internus which articulates with the quadrate, a processus ccessorius anterior which is connected with the quadrate by a ligament, and a ligamentary connexion between the pars superior of the insertion plate and processus paroticus. The processus accessorius posterior-ceratohyal connexion was not noticed. There is also a muscle (a part of M. stylohyoid) spanning the pars superior and crista parotica. The pars superior-paroticus ligamentary connexion, with the chorda tympani running laterally to it, is homologized with the laterohyal of Sphenodon and the crocodile. 8. The hyoid apparatus shows a processus. lingualis and cornuhyale (paired hypo- and ceratohyals) arising from a median basihyal and two pairs of ceratobranchials. 9. In the osteocranium, the oto-occipital of each side is formed by the fusion of opisthotic and exoccipital, while the supraoccipital is formed by an ossification in the tectum and its fusion with the two epiotics formed in the sinus region of the otic capsule. The basioccipital and the composite ‘sphenoid’ are not united. The pleurosphenoid ossifies in the pila antotica. The epipterygoid is connected at its dorsal end with the parietal by a ligament, and ventromedially it is free from the meniscus cartilage. The frontals and parietals are paired in the stage examined, and in the adult the parietals of each side fuse, as also the frontals.

A 3-Dimensional Model of the Human Round Window Membrane

2019 ◽  
Vol 128 (6_suppl) ◽  
pp. 103S-110S
Author(s):  
Yasuya Nomura ◽  
Toru Tanaka ◽  
Hitome Kobayashi ◽  
Yurika Kimura ◽  
Yurie Soejima ◽  
...  
Keyword(s):  
Cross Sections ◽  
Laser Scanning ◽  
Round Window ◽  
Gross Anatomy ◽  
Laser Scanning Microscopy ◽  
Round Window Membrane ◽  
Dimensional Model ◽  
Anterior Portion ◽  
Posterior Portion ◽  
3 Dimensional

Objectives: The round window membrane (RWM) is small in size, making it difficult to clarify its shape and structure. The authors examined a 40x magnified 3-dimensional model of the human RWM to clarify its morphologic aspects and characteristics. Methods: An RWM specimen was obtained from an archival, formalin-fixed, decalcified, left temporal bone of an 84-year-old female cadaver. The data obtained by laser scanning microscopy were input into a 3-dimensional printer. After a model of the RWM was created, the following features were examined: striae on the surfaces, curvatures, thickness, and areas. Cross sections of the original specimen were made for histological observations. Results: The contour of this RWM model was approximately elliptic, with a saddle shape. When illuminated from the scala tympani side, the surface facing the fossula exhibited dark anterior and clear posterior portions. A borderline appeared where the 2 portions were bound along the short axis of the ellipse. This borderline was identified as the line of inflection. Collagen fibers were shown to run parallel to the borderline in the posterior portion but were fanned out in the anterior portion. Conclusions: The magnified 3-dimensional model clarified gross anatomy and characteristics of the RWM. It is good teaching material for small tissues, such as the RWM.

scholarly journals Conserved genomic neighborhood is a strong but no perfect indicator for a direct interaction of microbial gene products

2020 ◽  
Vol 21 (1) ◽  
Author(s):  
Robert Esch ◽  
Rainer Merkl
Keyword(s):  
Gene Product ◽  
Protein Complexes ◽  
Sequence Similarity ◽  
False Positive Rate ◽  
Direct Interaction ◽  
Interaction Partner ◽  
Gene Products ◽  
Genomic Context ◽  
Positive Rate ◽  
Genomic Neighborhood

Abstract Background The order of genes in bacterial genomes is not random; for example, the products of genes belonging to an operon work together in the same pathway. The cotranslational assembly of protein complexes is deemed to conserve genomic neighborhoods even stronger than a common function. This is why a conserved genomic neighborhood can be utilized to predict, whether gene products form protein complexes. Results We were interested to assess the performance of a neighborhood-based classifier that analyzes a large number of genomes. Thus, we determined for the genes encoding the subunits of 494 experimentally verified hetero-dimers their local genomic context. In order to generate phylogenetically comprehensive genomic neighborhoods, we utilized the tools offered by the Enzyme Function Initiative. For each subunit, a sequence similarity network was generated and the corresponding genome neighborhood network was analyzed to deduce the most frequent gene product. This was predicted as interaction partner, if its abundance exceeded a threshold, which was the frequency giving rise to the maximal Matthews correlation coefficient. For the threshold of 16%, the true positive rate was 45%, the false positive rate 0.06%, and the precision 55%. For approximately 20% of the subunits, the interaction partner was not found in a neighborhood of ± 10 genes. Conclusions Our phylogenetically comprehensive analysis confirmed that complex formation is a strong evolutionary factor that conserves genome neighborhoods. On the other hand, for 55% of the cases analyzed here, classification failed. Either, the interaction partner was not present in a ± 10 gene window or was not the most frequent gene product.

scholarly journals Silent rain: does the atmosphere-mediated connectivity between microbiomes influence bacterial evolutionary rates?

2020 ◽  
Vol 96 (7) ◽  
Author(s):  
Matti Jalasvuori
Keyword(s):  
Microbial Communities ◽  
Gene Product ◽  
Genetic Divergence ◽  
Epistatic Interaction ◽  
Genetic Material ◽  
Evolutionary Rates ◽  
Gene Products ◽  
Vast Number ◽  
Number Of Bacteria

ABSTRACT Air carries a vast number of bacteria and viruses over great distances all the time. This leads to continuous introduction of foreign genetic material to local, established microbial communities. In this perspective, I ask whether this silent rain may have a slowing effect on the overall evolutionary rates in the microbial biosphere. Arguably, the greater the genetic divergence between gene ‘donors’ and ‘recipients’, the greater the chance that the gene product has a deleterious epistatic interaction with other gene products in its genetic environment. This is due to the long-term absence of check for mutual compatibility. As such, if an organism is extensively different from other bacteria, genetic innovations are less probable to fit to the genome. Here, genetic innovation would be anything that elevates the fitness of the gene vehicle (e.g. bacterium) over its contemporaries. Adopted innovations increase the fitness of the compatible genome over incompatible ones, thus possibly tempering the pace at which mutations accumulate in existing genomes over generations. I further discuss the transfer of bacteriophages through atmosphere and potential effects that this may have on local dynamics and perhaps phage survival.

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