Faculty Opinions recommendation of Basolateral protrusion and apical contraction cooperatively drive Drosophila germ-band extension.

2020 ◽  
Author(s):  
Ann Sutherland ◽  
Alyssa Lesko
Keyword(s):  
Germ Band

A group of genes required for maintenance of the amnioserosa tissue in Drosophila

Development ◽  
1996 ◽  
Vol 122 (5) ◽  
pp. 1343-1352 ◽  
Author(s):  
L.H. Frank ◽  
C. Rushlow
Keyword(s):  
Cell Death ◽  
Cell Loss ◽  
Dorsal Side ◽  
Drosophila Embryo ◽  
Epithelial Tissue ◽  
Dorsoventral Patterning ◽  
Wild Type ◽  
Germ Band ◽  
Initial Development

The amnioserosa is an extraembryonic, epithelial tissue that covers the dorsal side of the Drosophila embryo. The initial development of the amnioserosa is controlled by the dorsoventral patterning genes. Here we show that a group of genes, which we refer to as the U-shaped-group (ush-group), is required for maintenance of the amnioserosa tissue once it has differentiated. Using several molecular markers, we examined amnioserosa development in the ush-group mutants: u-shaped (ush), hindsight (hnt), serpent (srp) and tail-up (tup). Our results show that the amnioserosa in these mutants is specified correctly and begins to differentiate as in wild type. However, following germ-band extension, there is a premature loss of the amnioserosa. We demonstrate that this cell loss is a consequence of programmed cell death (apoptosis) in ush, hnt and srp, but not in tup. We discuss the role of the ush-group genes in maintaining the amnioserosa's viability. We also discuss a possible role for the amnioserosa in germ-band retraction in light of these mutants' unretracted phenotype.

scholarly journals BIOMETRIC STUDIES ON OLIGOMELIC INDIVIDUALS OF THE SPIDER TEGENARIA ATRICA (ARTHROPODA, ARACHNIDA) / BADANIA BIOMETRYCZNE OSOBNIKÓW OLIGOMELICZNYCH PAJĄKA TEGENARIA ATRICA (ARTHROPODA, ARACHNIDA)

2013 ◽  
Vol 58 (1-2) ◽  
pp. 19-28
Author(s):  
Julita Templin ◽  
Teresa Napiórkowska
Keyword(s):  
Surface Area ◽  
Compensatory Growth ◽  
Carapace Length ◽  
Anatomical Structure ◽  
The Body ◽  
Developmental Anomaly ◽  
Germ Band ◽  
Influence Of Temperature ◽  
Growth Increase ◽  
The Right

Abstract Oligomely is a type of developmental anomaly occurring in embryos of the spider Tegenaria atrica C.L. Koch under the teratogenic influence of temperature. This anomaly is of metameric origin, as it results from a disorder of metamere formation on the germ band during embryogenesis, resulting in the absence of one half or the whole metamere. In such a case, one or more appendages are missing on one or both sides of the body in a spider leaving a chorion. This anomaly induces changes both in the anatomical structure and exoskeleton of a spider (deformation of carapace and sternum). Carapace length and sternum area were measured, as well as the duration of the subsequent nymph stages of oligomelic individuals with one of the walking appendages missing (always on the right side of the body) was recorded. The consecutive nymph stages of oligomelic individuals lasted for a much shorter time compared with control specimens. This acceleration of development is probably to offset losses incurred during embryogenesis. In the early postembryogenesis, oligomelic specimens exhibited shorter carapace length and smaller surface area of the sternum compared to control individuals, which resulted from the lack of half of the metamere corresponding to the missing leg. However, in older nymph stages, a strong tendency for the faster growth of both carapace and sternum was observed, which can be defined as a compensatory growth increase making up for the losses caused by the anomaly.

scholarly journals The Drosophila SRF homolog is expressed in a subset of tracheal cells and maps within a genomic region required for tracheal development

Development ◽  
1994 ◽  
Vol 120 (4) ◽  
pp. 743-753 ◽  
Author(s):  
M. Affolter ◽  
J. Montagne ◽  
U. Walldorf ◽  
J. Groppe ◽  
U. Kloter ◽  
...  
Keyword(s):  
Serum Response Factor ◽  
Genomic Region ◽  
Nucleotide Sequence Analysis ◽  
Germ Band ◽  
Correct Position ◽  
Tracheal System ◽  
Sequence Identity ◽  
Distinct Subset ◽  
Drosophila Homolog ◽  
Serum Response

The Drosophila homolog of the vertebrate serum response factor (SRF) was isolated by low stringency hybridization. Nucleotide sequence analysis revealed that the Drosophila SRF homolog (DSRF) codes for a protein that displays 93% sequence identity with human SRF in the MADS domain, the region required for DNA binding, dimerization and interaction with accessory factors. The DSRF gene is expressed during several phases of embryonic development. In the egg, both the RNA and the protein are maternal in origin and slowly decrease in amount during gastrulation. After germ band retraction, high levels of zygotic expression are observed in a distinct subset of peripheral tracheal cells distributed throughout the embryo. Many of these cells are at the tip of tracheal branches and are in direct contact with the target tissues. The DSRF gene was mapped to position 60C on the second chromosome, and overlapping deficiencies which remove the gene were identified. Analysis of tracheal development in embryos carrying these deletions revealed a degeneration of most of the major branches of the tracheal system. Although the initial migration of tracheal cells was not affected in those deficient embryos, many tracheal cells appeared not to maintain their correct position and continued to migrate. Thus, the DSRF gene might play a role in the proper formation and maintenance of the trachea.

Expression of engrailed during segmentation in grasshopper and crayfish

Development ◽  
1989 ◽  
Vol 107 (2) ◽  
pp. 201-212 ◽  
Author(s):  
N.H. Patel ◽  
T.B. Kornberg ◽  
C.S. Goodman
Keyword(s):  
Monoclonal Antibody ◽  
Cell Proliferation ◽  
Cell Division ◽  
Embryonic Stage ◽  
Germ Band ◽  
Segmentation Genes ◽  
Pair Rule ◽  
Drosophila Embryos ◽  
The Way

We have used a monoclonal antibody that recognizes engrailed proteins to compare the process of segmentation in grasshopper, crayfish, and Drosophila. Drosophila embryos rapidly generate metameres during an embryonic stage characterized by the absence of cell division. In contrast, many other arthropod embryos, such as those of more primitive insects and crustaceans, generate metameres gradually and sequentially, as cell proliferation causes caudal elongation. In all three organisms, the pattern of engrailed expression at the segmented germ band stage is similar, and the parasegments are the first metameres to form. Nevertheless, the way in which the engrailed pattern is generated differs and reflects the differences in how these organisms generate their metameres. These differences call into question what role homologues of the Drosophila pair-rule segmentation genes might play in other arthropods that generate metameres sequentially.

The degree of determination of the early embryo of Schistocerca gregaria (Forskål) (Orthoptera: Acrididae)

Development ◽  
1971 ◽  
Vol 25 (3) ◽  
pp. 277-299
Author(s):  
S. K. Moloo
Keyword(s):  
Early Development ◽  
Schistocerca Gregaria ◽  
Early Embryo ◽  
Germ Band ◽  
Early Cleavage ◽  
Band Formation ◽  
Zygote Nucleus ◽  
Young Embryo ◽  
Blastoderm Stage

The degree of determination of the young embryo of S. gregaria has been investigated using ligation, thermocautery and centrifugation techniques. From the overall results, it is suggested that the early development of the embryo is mediated by two physiological centres. The formation of the germ rudiment is controlled by an activation centre located in the periplasm round the posterior end of the egg. This centre is already present at the zygote nucleus stage and is essential during the very early cleavage period. The differentiation of the germ band is induced by the activity of a second centre, the differentiation centre, located in the presumptive thorax. It apparently becomes established at least by the late blastoderm stage and its activity continues during the period of germ-band formation. During the late cleavage and early blastoderm stages, the egg is labile and the embryo is therefore able to normalize its development after part or parts of the germinal Anlage have been cauterized, removed or displaced. The differentiation centre completes its functions by the beginning of gastrulation. Thereafter, the embryo is determined. The embryo can regulate its size at least up to the gastrulation stage provided that a certain minimum amount of usable yolk is available. The development of the serosa is not under the control of either centre. This structure seems to be capable of regeneration providing that a part of the extra-embryonic blastoderm remains intact.

Memoirs: The Embryonic Development of the Stick-Insect, Carausius morosus

1936 ◽  
Vol s2-78 (311) ◽  
pp. 487-511
Author(s):  
A. J. THOMAS
Keyword(s):  
Embryonic Development ◽  
Stick Insect ◽  
Malpighian Tubules ◽  
Germ Band ◽  
Ventral Plate ◽  
Carausius Morosus ◽  
Gut Epithelium ◽  
Cleavage Nucleus ◽  
Endodermal Cells ◽  
Late Stages

1. The maturation of the egg takes place in the ovarian tube, and is immediately followed by the formation of the cleavagenucleus and its division into many nuclei. 2. The entire products of the cleavage-nucleus migrate to the surface to form the blastoderm. Cleavage of the yolk was not observed even in late stages. Yolk-cells are absent when the blastoderm is being formed. 3. Primitive endodermal cells are proliferated from the middle of the germ-band, and form a membrane between the germ-band and the yolk. The membrane is present only in embryonic stages; some of the cells proliferated wander into the yolk and act as vitellophags. 4. Mesoderm is formed by proliferation of cells from the ventral plate. It is preceded by the formation of a shallow gastrular furrow, and from the bottom of this furrow proliferation takes place. The mesoderm becomes arranged in segmental masses. 5. Two masses of cells proliferated at the anterior and posterior ends of the germ-band are shown to be the endodermal rudiments from which the mid-gut epithelium is formed. The invaginations of the stomodaeum and proctodaeum grow against these masses and carry parts of the proliferating areas near their blind ends. It is shown that the various methods of mid-gut formation which have been described could be reconciled with the process described in Carausius. 6. The hinder end of the mid-gut is flanked by two plates of ectoderm which are forward extensions of the proctodaeum. Into these extensions the Malpighian tubules open, and, as their histology is identical with that of these extensions and widely different from that of the mid-gut, these tubules must be ectodermal in nature. 7. The formation of the amnion and serosa are described.

The pattern of cell death in fushi tarazu, a segmentation gene of Drosophila

Development ◽  
1988 ◽  
Vol 104 (3) ◽  
pp. 447-451 ◽  
Author(s):  
L. Magrassi ◽  
P.A. Lawrence
Keyword(s):  
Cell Death ◽  
Wild Type ◽  
Germ Band ◽  
Fushi Tarazu ◽  
Larval Cuticle ◽  
Dividing Cells ◽  
In The Wild ◽  
Indirect Consequence ◽  
Dying Cells ◽  
Pair Rule

The pair-rule mutant, fushi tarazu, causes deletion of alternate metameres. Here we show that there is cell death in the mutant which begins at the completion of germ band extension. We map the dying cells in the epidermis; they occur scattered all over those regions that, in the wild type, would form the even-numbered parasegments and are also found in posterior parts of the odd-numbered parasegments. In the affected zones, dying and dividing cells are intermingled; we suggest that cells from these zones may still give descendents that contribute to the larval cuticle. Cell death is not limited to those cells that would normally express ftz+, suggesting that it is some indirect consequence of the abnormal situation in the mutant embryo.

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