The effect of lethal mutations and deletions within the bithorax complex upon the identity of caudal metameres in the Drosophila embryo

Development ◽  
1986 ◽  
Vol 93 (1) ◽  
pp. 153-166
Author(s):  
J. R. S. Whittle ◽  
S. Y. K. Tiong ◽  
C. E. Sunkel
Keyword(s):  
Abdominal Segment ◽  
Sense Organ ◽  
Drosophila Embryo ◽  
Bithorax Complex ◽  
Sense Organs ◽  
Head Region ◽  
Lethal Mutations ◽  
Segment 8 ◽  
Derivatives Of ◽  
Cuticular Structures

Mutations and deletions of the abdA and AbdB functions in the bithorax complex of Drosophila melanogaster have been examined for their effect upon the hypodermal derivatives of the caudal segments of the embryo, employing light- and scanning electron microscopy. No cuticular structures located posterior to the denticle belt of abdominal segment 8 are affected in abdA− embryos. Embryos of AbdB− genotype no longer have six of the seven pairs of sense organs present in this region, lack posterior spiracles but instead have sclerotized cuticle and sense organs typical of the head region and a rudimentary extra ventral denticle belt. The anal pads, tuft and sense organ 1 do not require BX-C functions for their specification. We discuss the provenance of these cuticular structures and the domain of function of elements within the bithorax complex in terms of parasegmental metameric units.

The expression of a zebrafish gene homologous to Drosophila snail suggests a conserved function in invertebrate and vertebrate gastrulation

Development ◽  
1993 ◽  
Vol 119 (4) ◽  
pp. 1107-1118 ◽  
Author(s):  
M. Hammerschmidt ◽  
C. Nusslein-Volhard
Keyword(s):  
Zinc Finger Protein ◽  
Paraxial Mesoderm ◽  
Drosophila Embryo ◽  
Head Region ◽  
Dorsal Midline ◽  
Ventral Furrow ◽  
Finger Protein ◽  
Transcription Data ◽  
Derivatives Of

Snail, a zinc finger protein, is required for the formation of the ventral furrow and the mesoderm during gastrulation of the Drosophila embryo. snail homologues have been cloned from Xenopus and mouse. We have isolated a zebrafish homologue of snail, designated sna-1. Like its Drosophila counterpart, Sna-1 protein is nuclear. Maternal and zygotic sna-1 transcripts are ubiquitously distributed in zebrafish embryos of cleavage and blastula stages. In gastrulating embryos, sna-1 is expressed in involuting cells of the germ ring, but not in those at the dorsal midline, the presumptive notochordal region. After involution, the expression is maintained in the paraxial mesoderm and becomes prominent in the muscle pioneer precursors, followed by expression at the posterior somite boundaries. Later, sna-1 is expressed in neural crest and mesodermal derivatives of the head region. Sna-1 expression is induced in animal cap cells by activin A. The early sna-1 expression pattern in gastrulating zebrafish no tail (ntl) mutant embryos is normal except a reduction in the level of sna-1 transcription, suggesting that Ntl protein is not the key activator of sna-1 transcription in vivo, but might be involved in the enhancement or maintenance of sna-1 transcription. Data obtained in studies with ectopic ntl expression support this model.

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 Comparative genitalic morphology in ten genera of thread-legged bugs of the tribe Metapterini, and its phylogenetic importance (Hemiptera: Heteroptera: Reduviidae)

2018 ◽  
Vol 58 (1) ◽  
pp. 91-125 ◽  
Author(s):  
Valentina Castro-Huertas ◽  
Dimitri Forero ◽  
Jocelia Grazia
Keyword(s):  
Male Genitalia ◽  
Abdominal Segment ◽  
Data Matrix ◽  
Potential Usefulness ◽  
Bursa Copulatrix ◽  
Wing Polymorphism ◽  
Male And Female ◽  
Basal Process ◽  
Segment 8 ◽  
Assassin Bug

The assassin bug tribe Metapterini belongs to the subfamily Emesinae (Hemiptera: Heteroptera: Reduviidae). Morphologically, it is characterized by the conspicuous basal process of the posteroventral series in the foreleg and the presence of wing polymorphism, with a high proportion of the genera with micropterous or apterous species. Here, the male and female ectodermal genitalic structures are documented for ten genera and twenty-three species of Metapterini, including eight species of the speciose genus Ghilianella Spinola, 1850. Descriptions and digital macrophotographs are provided for abdominal segment 8, pygophore, parameres, and phallus of the male, and for tergite 8, tergite 9, gonocoxae, gonapophyses, gonoplac, and bursa copulatrix of the female. The asymmetric male genitalia within Emesinae are discussed. From this morphological documentation sixty six phylogenetic characters are coded, presented as a data matrix and analyzed cladistically, and their potential usefulness for resolving relationships among Metapterini is discussed.

Developmental effects of some newly induced Ultrabithorax alleles of Drosophila

Development ◽  
1982 ◽  
Vol 68 (1) ◽  
pp. 211-234
Author(s):  
Stephen Kerridge ◽  
Gines Morata
Keyword(s):  
Chromosomal Aberrations ◽  
Abdominal Segment ◽  
Larval Period ◽  
Additive Effect ◽  
Bithorax Complex ◽  
Induced Mutations ◽  
Heterozygous Condition ◽  
X Ray ◽  
Developmental Effects ◽  
Blastoderm Stage

Nine X-ray-induced mutations of the bithorax complex (BX-C) have been isolated and characterized. They all show the typical features of the Ultrabithorax mutations. They are homozygous lethal, produce a slight enlargement of the haltere in heterozygous condition and fail to complement the mutations at the bx, bxd and pbx loci. Some of them are associated with chromosomal aberrations in the regions 89E 1-4, where the BX-C lies, while others appear normal cytologically. The effect of six of these mutants in the adult cuticle has been studied, producing mutant marked clones in heterozygous individuals. The clones were generated by X-radiation at two points in development: the blastoderm stage and the second larval period. In all cases mutant clones showed the same phenotype: clones appearing in the dorsal structures transform metathorax and first abdominal segment towards mesothorax. That is the additive effect of bx, bxd and pbx mutations. Clones in the legs, if induced during the larval period, show an effect homologous to that seen in the dorsal structures. However, when produced at blastoderm they show in addition a transformation of the posterior second (mesothoracic) and third (metathoracic) legs into the posterior first (prothoracic) leg. This transformation, named postprothorax (ppx) has been recently described for the alleles Ubx130 and Ubx1 (Morata & Kerridge, 1981) and appears to be general for the Ubxmutations. It is concluded that the realm of action of the Ubx gene is defined by part of the rflesothoracic segment (posterior second leg compartment) and the entire metathoracic and first abdominal segments.

The helix-loop-helix extramacrochaetae protein is required for proper specification of many cell types in the Drosophila embryo

Development ◽  
1994 ◽  
Vol 120 (9) ◽  
pp. 2555-2566 ◽  
Author(s):  
P. Cubas ◽  
J. Modolell ◽  
M. Ruiz-Gomez
Keyword(s):  
Cell Types ◽  
Drosophila Embryo ◽  
Cell Contact ◽  
Cell Recognition ◽  
Cell Specification ◽  
Helix Loop Helix ◽  
Attachment Sites ◽  
Different Cell Types ◽  
Derivatives Of ◽  
Basic Region

The Drosophila Extramacrochaetae protein antagonizes the proneural function of the Achaete and Scute proteins in the generation of the adult fly sensory organs. Extra-macrochaetae sequesters these basic-region-helix-loop-helix transcription factors as heterodimers inefficient for binding to DNA. We show that, during embryonic development, the extramacrochaetae gene is expressed in complex patterns that comprise derivatives of the three embryonic layers. Expression of extramacrochaetae often precedes and accompanies morphogenetic movements. It also occurs at regions of specialized cell-cell contact and/or cell recognition, like the epidermal part of the muscle attachment sites and the differentiating CNS. The insufficiency of extramacrochaetae affects most tissues where it is expressed. The defects suggest faulty specification of different cell types and result in impairment of processes as diverse as cell proliferation and commitment, cell adhesion and cell recognition. If Extramacrochaetae participates in cell specification by dimerizing with basic-region-helix-loop-helix proteins, the variety of defects and tissues affected by the insufficiency of extramacrochaetae suggests that helix-loop-helix proteins are involved in many embryonic developmental processes.

The fine morphology of the osphradial sense organs of the mollusca. III. Placophora and bivalvia

1987 ◽  
Vol 315 (1169) ◽  
pp. 37-61 ◽  
Keyword(s):  
Fine Structure ◽  
Sense Organ ◽  
Mantle Cavity ◽  
Sense Organs ◽  
Physiological Evidence ◽  
Anal Papillae ◽  
Fine Morphology

The fine morphology of the osphradia of six placophorans and eight bivalves, representing all major subgroups of both classes, is described. In addition the branchial and lateral sense organs of Lepidopleurus cajetanus (Placophora) have been investigated ultrastrucurally. Whereas osphradial fine structure is very uniform within the Bivalvia there are differences between Ischnochitonina and Acanthochitonina, supporting the separation of both groups. Major differences in the conditions of the mantle cavity divide Recent Placophora into the orders Lepidopleurida and Chitonida. The homology of the molluscan osphradium throughout the phylum is discussed in detail. It is concluded that the terminal sense organ (Caudofoveata, Solenogastres), the adanal sensory stripes (Placophora—Chitonida), the interbranchial and post-anal papillae of Nautilus (Cephalopoda), and the organ of Lacaze (Gastropoda-Basommatophora) are homologous with the organs of Spengel (Prosobranchia, Opisthobranchia, Bivalvia), all to be called osphradial sense organs (or osphradia). After discussion it is concluded that the osphradium is a chemoreceptor and not a mechanoreceptor as suggested by many authors. This is shown by the physiological evidence so far reported but mainly by the existence of paddle cilia in the osphradial epithelia throughout the Mollusca, which are typical of molluscan chemoreceptors. It is suggested that the osphradium is primarily used in sexual biology (coordination of spawning, search for a mate), a role altered within the Gastropoda (search for food, osmoreceptor, p O2 -receptor).

scholarly journals The Fab-7 element of the bithorax complex attenuates enhancer-promoter interactions in the Drosophila embryo.

1996 ◽  
Vol 10 (24) ◽  
pp. 3195-3201 ◽  
Author(s):  
J Zhou ◽  
S Barolo ◽  
P Szymanski ◽  
M Levine
Keyword(s):  
Drosophila Embryo ◽  
Bithorax Complex

Genetic determinants of sense organ identity in Drosophila: regulatory interactions between cut and poxn

Development ◽  
1995 ◽  
Vol 121 (9) ◽  
pp. 3111-3120 ◽  
Author(s):  
M. Vervoort ◽  
D. Zink ◽  
N. Pujol ◽  
K. Victoir ◽  
N. Dumont ◽  
...  
Keyword(s):  
Regulatory Region ◽  
Sense Organ ◽  
Sense Organs ◽  
Genetic Determinants ◽  
Regulatory Interactions ◽  
Organ Identity ◽  
Small Domain

Two genes involved in defining the type of sense organ have been identified in Drosophila. The gene cut differentiates the external sense organs (where it is expressed) from the chordotonal organs (where it is not); among the external sense organs poxn differentiates the poly-innervated organs (where it is expressed) from the mono-innervated organs (where it is not). Here we show that the expression of poxn in normal embryos does not depend on cut, and that poxn is capable of inducing the expression of cut. We have identified a small domain of the very large cut regulatory region as a likely target for activation by poxn.

Transcription activates repressed domains in theDrosophilabithorax complex

Development ◽  
2002 ◽  
Vol 129 (21) ◽  
pp. 4923-4930 ◽  
Author(s):  
Welcome Bender ◽  
Daniel P. Fitzgerald
Keyword(s):  
Abdominal Segment ◽  
Mutant Phenotype ◽  
P Element ◽  
Bithorax Complex ◽  
Regulatory Regions ◽  
P Elements

A series of mutations have been recovered in the bithorax complex of D. melanogaster that transform the first segment of the abdomen into a copy of the second or third abdominal segment. These dominantUltraabdominal alleles are all associated with P element insertions which are transcribed in the first abdominal segment. The transcripts proceed past the end of the P element for up to 50 kb, extending through the regulatory regions for the second and third abdominal segments. Blocking transcription from the P element promoter reverts the mutant phenotype. Previously identified Ultraabdominal alleles, not associated with P elements, also show abnormal transcription of the same region.

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