scholarly journals Delta and Hairy establish a periodic prepattern that positions sensory bristles in Drosophila legs

2006 ◽  
Vol 293 (1) ◽  
pp. 64-76 ◽  
Author(s):  
Meghana Joshi ◽  
Kathryn T. Buchanan ◽  
Stuti Shroff ◽  
Teresa V. Orenic
Keyword(s):  
Sensory Bristles

mirror, a Drosophila homeobox gene in the Iroquois complex, is required for sensory organ and alula formation

Development ◽  
1998 ◽  
Vol 125 (7) ◽  
pp. 1217-1227 ◽  
Author(s):  
B.T. Kehl ◽  
K.O. Cho ◽  
K.W. Choi
Keyword(s):  
Protein Structure ◽  
Genetic Analysis ◽  
Genetic Map ◽  
Body Wall ◽  
Homeobox Gene ◽  
Structure And Function ◽  
The Other ◽  
Complex Region ◽  
Sensory Bristles ◽  
And Function

The Drosophila notum, the dorsal body wall of the thorax, is subdivided genetically into longitudinal domains (Calleja, M., Moreno, E., Pelaz, S. and Morata, G. (1996) Science 274, 252–255). Two homeobox genes clustered in the iroquois complex, araucan and caupolican, regulate proneural genes and are required for development of sensory bristles in the lateral notum (Gomez-Skarmeta, J. L., del Corral, R. D., de la Calle-Mustienes, E., Ferres-Marco, D. and Modolell, J. (1996) Cell 85, 95–105). An iroquois-related homeobox gene, mirror, was recently isolated and is localized close to the iroquois complex region (McNeil, H., Yang, C.-H., Brodsky, M., Ungos, J. and Simon, M. A. (1997) Genes and Development 11, 1073–1082; this study). We show that mirror is required for the formation of the alula and a subset of sensory bristles in the lateral domain of the notum. Genetic analysis suggests that mirror and the other iroquois genes interact to form the alula as well as the sensory organs. Based on similarities between mirror and the iroquois genes in their genetic map positions, expression, protein structure and function, mirror is considered a new member of the iroquois complex and is involved in prepatterning sensory precursor cells in the lateral notum.

scuteexpression inCalliphora vicinareveals an ancestral pattern of longitudinal stripes on the thorax of higher Diptera

Development ◽  
2002 ◽  
Vol 129 (3) ◽  
pp. 563-572 ◽  
Author(s):  
Daniela Pistillo ◽  
Nick Skaer ◽  
Pat Simpson
Keyword(s):  
Expression Pattern ◽  
Regulatory Elements ◽  
Calliphora Vicina ◽  
Transcriptional Activators ◽  
Gene Complex ◽  
Secondary Loss ◽  
Evolutionary Changes ◽  
Sensory Bristles ◽  
And Function ◽  
Bristle Patterns

In Drosophila the stereotyped arrangement of sensory bristles on the notum is determined by the tightly regulated control of transcription of the achaete-scute (ac-sc) genes which are expressed in small proneural clusters of cells at the sites of each future bristle. Expression relies on a series of discrete cis-regulatory elements present in the ac-sc gene complex that are the target of the transcriptional activators pannier (pnr) and the genes of the iroquois complex. Stereotyped bristle patterns are common among species of acalyptrate Schizophora such as Drosophila, and are thought to have derived from an ancestral pattern of four longitudinal rows extending the length of the scutum, through secondary loss of bristles. To investigate evolutionary changes in bristle patterns and ac-sc regulation by pnr, we have isolated homologues of these genes from Calliphora vicina, a species of calyptrate Schizophora separated from Drosophila by at least 100 million years. Calliphora vicina displays a pattern of four rows of bristles on the scutum resembling the postulated ancestral one. We find that sc in Calliphora is expressed in two longitudinal stripes on the medial scutum that prefigure the development of the rows of acrostichal and dorsocentral bristles. This result suggests that a stripe-like expression pattern of sc may be an ancestral feature and may have preceded the evolution of proneural clusters. The implications for the evolution of the cis-regulatory elements responsible for sc expression in the proneural clusters of Drosophila, and function of Pnr are discussed.

Determination of sensory bristles and pattern formation in Drosophila

1979 ◽  
Vol 70 (2) ◽  
pp. 438-452 ◽  
Author(s):  
Alain Ghysen ◽  
Jean Richelle
Keyword(s):  
Pattern Formation ◽  
Sensory Bristles

SEM studies of architecture of thoracic chelate appendages of fresh-water prawn, Macrobrachium lamarrei H.M. Edwards (Decapoda-Palaemonidae)

1990 ◽  
Vol 48 (3) ◽  
pp. 508-509
Author(s):  
U. D. Sharma ◽  
Sanjive Shukla
Keyword(s):  
Fresh Water ◽  
Proximal Part ◽  
Different Types ◽  
Central Shaft ◽  
Sensory Bristles ◽  
Food Manipulation ◽  
Sem Studies

Chelate legs of certain crustaceans help in detection and capture, and finally carry the food to the trophic devices. The first and second pair of chelate leges (Periodpods) of M. lamarrei were studied to understand their role in food manipulation. These appendages were detached from the prawn, fixed, and processed. Samples were observed and photographed under an SEM (JEOL JSM 35C).Six types of bristles/setae have been observed on these podomeres (Figs. 1-11). However, the bristles on podomeres of the second leg are sparsely arranged. The toothed and serrate setae are also missing from the propodite of the second leg. The aboral and adoral surfaces of propodite of I chelate leg have two different types of sensory bristles. The serrate setae are aboral, each with a central shaft (120 μm long) and bilateral projections (15.5. μm long); the adoral ones are toothed setae (297 μm) with sunken base and denticulation at the distal end. A third type, the sawtoothed setae, are on the proximal part of the dactylopodite. These are arranged in 7-8 rows of 4-9 setae each.

Lateral inhibition and the development of the sensory bristles of the adult peripheral nervous system of Drosophila

Development ◽  
1990 ◽  
Vol 109 (3) ◽  
pp. 509-519 ◽  
Author(s):  
P. Simpson
Keyword(s):  
Small Groups ◽  
Neural Cells ◽  
Cellular Interactions ◽  
Equivalence Group ◽  
Neural Fate ◽  
Neurogenic Genes ◽  
Sensory Bristles ◽  
Proneural Cluster ◽  
Molecular Nature ◽  
Bristle Pattern

Cells in the neurectoderm of Drosophila face a choice between neural and epidermal fates. On the notum of the adult fly, neural cells differentiate sensory bristles in a precise pattern. Evidence has accumulated that the bristle pattern arises from the spatial distribution of small groups of cells, proneural clusters, from each of which a single bristle will result. One class of genes, which includes the genes of the achaete-scute complex, is responsible for the correct positioning of the proneural clusters. The cells of a proneural cluster constitute an equivalence group, each of them having the potential to become a neural cell. Only one cell, however, will adopt the primary, dominant, neural fate. This cell is selected by means of cellular interactions between the members of the group, since if the dominant cell is removed, one of the remaining, epidermal, cells will switch fates and become neural. The dominant cell therefore prevents the other cells of the group from becoming neural by a phenomenon known as lateral inhibiton. They, then, adopt the secondary, epidermal, fate. A second class of genes, including the gene shaggy and the neurogenic genes mediate this process. There is some evidence that a proneural cluster is composed of a small number of cells, suggesting a contact-based mechanism of communication. The molecular nature of the protein products of the neurogenic genes is consistent with this idea.

Effects of Sub-Lethal High Temperature on An Insect, Rhodnius Prolixus (Stål.)

1968 ◽  
Vol 48 (3) ◽  
pp. 455-463
Author(s):  
A. Y. K. OKASHA
Keyword(s):  
Heat Treatment ◽  
High Temperature ◽  
Larval Stage ◽  
Prolonged Exposure ◽  
Rhodnius Prolixus ◽  
Malpighian Tubules ◽  
Sensory Bristles ◽  
Harmful Effects

1. The effect on moulting of exposing 1st-, 2nd-, 3rd- and 4th-stage larvae of Rhodnius to 36.5° C. immediately after feeding was studied. After transfer to normal temperature (28° C.) moulting is delayed; the duration of the delay is directly proportional to the period of exposure to high temperature. 2. Unfed larvae exposed to high temperature exhibit delayed moulting when placed at normal temperature after feeding, and prolonged exposure also inhibits micturition which normally occurs directly after feeding. 3. Since the Malpighian tubules appear to function normally, it is suggested that the inhibition of the mechanisms responsible for emptying the rectum results in the cessation of micturition. 4. The harmful effects on moulting of heat-treatment of unfed larvae can be eliminated by placing the exposed insects at normal temperature for an appropriate period before feeding. 5. Exposure to high temperature either before or after feeding results in the decrease and malformation of the sensory bristles and plaques in the next larval stage.

Notch regulates wingless expression and is not required for reception of the paracrine wingless signal during wing margin neurogenesis in Drosophila

Development ◽  
1995 ◽  
Vol 121 (9) ◽  
pp. 2813-2824 ◽  
Author(s):  
E.J. Rulifson ◽  
S.S. Blair
Keyword(s):  
Lateral Inhibition ◽  
Sensory Cells ◽  
Temperature Sensitive ◽  
Wing Margin ◽  
Signal Loss ◽  
Subsequent Formation ◽  
Notch Protein ◽  
Sensory Bristles ◽  
Narrow Stripe

In the developing wing margin of Drosophila, wingless is normally expressed in a narrow stripe of cells adjacent to the proneural cells that form the sensory bristles of the margin. Previous work has shown that this wingless is required for the expression of the proneural achaete-scute complex genes and the subsequent formation of the sensory bristles along the margin; recently, it has been proposed that the proneural cells require the Notch protein to properly receive the wingless signal. We have used clonal analysis of a null allele of Notch to test this idea directly. We found that Notch was not required by prospective proneural margin cells for the expression of scute or the formation of sensory precursors, indicating Notch is not required for the reception of wingless signal. Loss of Notch from proneural cells produced cell-autonomous neurogenic phenotypes and precocious differentiation of sensory cells, as would be expected if Notch had a role in lateral inhibition within the proneural regions. However, loss of scute expression and of sensory precursors was observed if clones substantially included the normal region of wingless expression. These ‘anti-proneural’ phenotypes were associated with the loss of wingless expression; this loss may be partially or wholly responsible for the anti-proneural phenotype. Curiously, Notch- clones limited to the dorsal or ventral compartments could disrupt wingless expression and proneural development in the adjacent compartment. Analysis using the temperature-sensitive Notch allele indicated that the role of Notch in the regulation of wingless expression precedes the requirement for lateral inhibition in proneural cells. Furthermore, overexpression of wingless with a heat shock-wingless construct rescued the loss of sensory precursors associated with the early loss of Notch.

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