Expression and function of the homoeotic genes Antennapedia and Sex combs reduced in the embryonic midgut of Drosophila

Development ◽  
1990 ◽  
Vol 109 (2) ◽  
pp. 289-303 ◽  
Author(s):  
R. Reuter ◽  
M.P. Scott
Keyword(s):  
Nervous System ◽  
Morphological Changes ◽  
Null Mutant ◽  
Sex Combs Reduced ◽  
Visceral Mesoderm ◽  
Sex Combs ◽  
Cell Layers ◽  
Specific Regulation ◽  
And Function ◽  
Mesodermal Tissue

Drosophila homoeotic genes control the formation of external morphological features of the embryo and adult, and in addition affect differentiation of the nervous system. Here we describe the morphogenetic events in the midgut that are controlled by the homoeotic genes Sex combs reduced (Scr) and Antennapedia (Antp). The midgut is composed of two cell layers, an inner endoderm and an outer visceral mesoderm that surround the yolk. Scr and Antp are expressed in the visceral mesoderm but not in the endoderm. The two genes are required for different aspects of the midgut morphogenesis. In Scr null mutant embryos the gastric caeca fail to form. Scr is expressed in the visceral mesoderm cells posterior to the primordia of the gastric caeca and appears to be indirectly required for the formation of the caeca. Antp is expressed in visceral mesoderm cells that overlie a part of the midgut where a constriction will form, and Antp null mutant embryos fail to form this constriction. An ultrastructural analysis of the midgut reveals that the visceral mesoderm imposes the constriction on the endoderm and the yolk. The mesodermal tissue contracts within the constriction and thereby penetrates the layer of the midgut endoderm. Microtubules participate in the morphological changes of the visceral mesoderm cells. The analysis of the expression of Scr in Antp mutant embryos revealed a case of tissue-specific regulation of Scr expression by Antp. In the epidermis, Antp has been shown to negatively regulate Scr, but it positively regulates Scr in the visceral mesoderm.

Homeotic genes have specific functional roles in the establishment of the Drosophila embryonic peripheral nervous system

Development ◽  
1992 ◽  
Vol 115 (1) ◽  
pp. 35-47 ◽  
Author(s):  
J.G. Heuer ◽  
T.C. Kaufman
Keyword(s):  
Nervous System ◽  
Peripheral Nervous System ◽  
Spatial Patterns ◽  
Ectopic Expression ◽  
Homeotic Genes ◽  
Sensory Organs ◽  
Sex Combs Reduced ◽  
Functional Roles ◽  
Visceral Mesoderm ◽  
Control Segment

The Drosophila embryonic peripheral nervous system (PNS) contains segment-specific spatial patterns of sensory organs which derive from the ectoderm. Many studies have established that the homeotic genes of Drosophila control segment specific characteristics of the epidermis, and more recently these genes have also been shown to control gut morphogenesis through their expression in the visceral mesoderm (Tremml, G. and Bienz, M. (1989), EMBO J. 8, 2677–2685). We report here the roles of homeotic genes in establishing the spatial patterns of sensory organs in the embryonic PNS. The PNS was examined in embryos homozygous for mutations in the homeotic genes Sex combs reduced (Scr), Antennapedia (Antp), Ultrabithorax (Ubx), abdominal-A (abd-A) and Abdominal-B (Abd-B) with antibodies that label specific subsets of sensory organs. Our results suggest that the homeotic genes have specific roles in establishing the correct spatial patterns of sensory organs in their normal domains of expression. In addition, we also report the effects of ectopic expression of the homeotic genes labial (lab), Deformed (Dfd), Scr, Antp or Ubx on the normal development of sensory organs in the embryonic PNS. Interestingly, while previous studies have concluded that ectopic expression of the homeotic genes Dfd, Scr and Antp has no effect on the segmental identity of the abdominal segments, our results demonstrate that this is not true. We show that ectopic expression of these genes does result in the disruption of the developing PNS in the abdomen. Our results are suggestive of a role for the homeotic gene products in regulating genes which are necessary for generating sensory progenitor cells in the developing PNS.

scholarly journals Distribution of the Sex combs reduced Gene Products in Drosophila melanogaster

Genetics ◽  
1987 ◽  
Vol 117 (1) ◽  
pp. 51-60
Author(s):  
James W Mahaffey ◽  
Thomas C Kaufman
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Temporal Distribution ◽  
Spatial And Temporal Distribution ◽  
Gene Products ◽  
Genetic Studies ◽  
Sex Combs Reduced ◽  
Sex Combs ◽  
The Central Nervous System ◽  
Differential Timing

ABSTRACT The spatial and temporal distribution of RNA and protein encoded by the homeotic Sex combs reduced (Scr) gene were examined during Drosophila development. The gene products are present in the epidermis of both the labial and first thoracic segments as would be predicted from prior genetic studies. However, the pattern in the central nervous system (CNS) and mesoderm is further restricted; the major expression located in the labial neuromere of the CNS and the mesoderm of the first thoracic segment. The spatial restriction within the CNS is correlated with and may be due to a differential timing of expression in the labial and first thoracic ectoderm. The labial ectoderm accumulates the Scr RNA prior to segregation of the neuroblasts while expression in the first thoracic ectoderm occurs after neuroblast segregation. The protein is also observed in the subesophageal ganglia of both larvae and adults, as well as in the labial and first thoracic imaginal discs. Surprisingly, the protein is also present to a lesser extent in second and third thoracic leg discs.

scholarly journals Genetic analysis of embryonic cis-acting regulatory elements of the Drosophila homeotic gene sex combs reduced.

Genetics ◽  
1995 ◽  
Vol 140 (2) ◽  
pp. 557-572 ◽  
Author(s):  
M J Gorman ◽  
T C Kaufman
Keyword(s):  
Expression Pattern ◽  
Chromosomal Rearrangements ◽  
Regulatory Elements ◽  
Homeotic Gene ◽  
Sex Combs Reduced ◽  
Cis Acting ◽  
Transcriptional Regulatory Elements ◽  
Visceral Mesoderm ◽  
Posterior Midgut ◽  
Sex Combs

Abstract The homeotic gene Sex combs reduced (Scr) of Drosophila melanogaster is expressed in the labial and prothoracic segments of the ectoderm, in parasegments two and three of the CNS, and in the visceral mesoderm of the anterior and posterior midgut. The mutationally defined function of Scr is to specify the identity of the labial and prothoracic segments and to control the development of the gastric caeca. The Scr locus occupies a chromosomal region of approximately 80 kb within the Antennapedia complex (ANT-C). To understand how Scr's spatiotemporal expression pattern is generated in the embryo, we have mapped its transcriptional regulatory elements using three approaches. First, we examined the expression pattern of Scr in embryos containing chromosomal rearrangements that remove potential Scr regulatory elements. Second, we made and analyzed a set of Scr minigene transformants. Third, we analyzed a set of Scr-lacZ enhancer tester constructs. Using more sensitive anti-SCR antisera, we discovered that Scr is expressed in tissues that were not previously thought to accumulate SCR: a stripe of ectodermal cells in the parasegment 2 region of stage 5 embryos, the embryonic salivary glands, and the dorsal ridge. Four DNA fragments that had previously been shown in an analysis of Scr-lacZ reporter constructs to contain putative Scr enhancer elements were found to have functional enhancers; similarly, another Scr fragment was found to contain a functional repressor. Our results suggest that regulation of Scr in the labial segment and the CNS requires the apparently synergistic action of multiple, widely spaced enhancer elements. Regulation in the prothorax also appears to be controlled by multiple enhancers:one complete pattern element and one subpattern element. In contrast, Scr regulation in the visceral mesoderm is controlled by an enhancer(s) located in only one DNA fragment.

Plant hormones, plant growth regulators

2014 ◽  
Vol 155 (26) ◽  
pp. 1011-1018 ◽  
Author(s):  
György Végvári ◽  
Edina Vidéki
Keyword(s):  
Nervous System ◽  
Growth And Development ◽  
Large Scale ◽  
Essential Role ◽  
Higher Plants ◽  
Structure And Function ◽  
Wide Sense ◽  
Large Scale Integration ◽  
Scale Integration ◽  
And Function

Plants seem to be rather defenceless, they are unable to do motion, have no nervous system or immune system unlike animals. Besides this, plants do have hormones, though these substances are produced not in glands. In view of their complexity they lagged behind animals, however, plant organisms show large scale integration in their structure and function. In higher plants, such as in animals, the intercellular communication is fulfilled through chemical messengers. These specific compounds in plants are called phytohormones, or in a wide sense, bioregulators. Even a small quantity of these endogenous organic compounds are able to regulate the operation, growth and development of higher plants, and keep the connection between cells, tissues and synergy beween organs. Since they do not have nervous and immume systems, phytohormones play essential role in plants’ life. Orv. Hetil., 2014, 155(26), 1011–1018.

Natural Products for the Treatment of Neurodegenerative Diseases

2020 ◽  
Vol 27 (34) ◽  
pp. 5790-5828 ◽  
Author(s):  
Ze Wang ◽  
Chunyang He ◽  
Jing-Shan Shi
Keyword(s):  
Nervous System ◽  
Natural Products ◽  
Neurodegenerative Diseases ◽  
Neuroprotective Effect ◽  
Rapid Development ◽  
New Drugs ◽  
Progressive Degeneration ◽  
Cord Injury ◽  
The Central Nervous System ◽  
And Function

Neurodegenerative diseases are a heterogeneous group of disorders characterized by the progressive degeneration of the structure and function of the central nervous system or peripheral nervous system. Alzheimer's Disease (AD), Parkinson's Disease (PD) and Spinal Cord Injury (SCI) are the common neurodegenerative diseases, which typically occur in people over the age of 60. With the rapid development of an aged society, over 60 million people worldwide are suffering from these uncurable diseases. Therefore, the search for new drugs and therapeutic methods has become an increasingly important research topic. Natural products especially those from the Traditional Chinese Medicines (TCMs), are the most important sources of drugs, and have received extensive interest among pharmacist. In this review, in order to facilitate further chemical modification of those useful natural products by pharmacists, we will bring together recent studies in single natural compound from TCMs with neuroprotective effect.

scholarly journals Ras1-Mediated Modulation of Drosophila Homeotic Function in Cell and Segment Identity

Genetics ◽  
1997 ◽  
Vol 146 (2) ◽  
pp. 619-628 ◽  
Author(s):  
Muriel Boube ◽  
Corinne Benassayag ◽  
Laurent Seroude ◽  
David L Cribbs
Keyword(s):  
Signal Transduction ◽  
Cell Signaling ◽  
Transcriptional Control ◽  
Opposite Effect ◽  
Signal Transduction Pathways ◽  
General Role ◽  
Sex Combs Reduced ◽  
Data Support ◽  
Sex Combs ◽  
Segmental Differentiation

Mutations of the Drosophila homeotic proboscipedia gene (pb; the Hox-A2/B2 homologue) provoke dose-sensitive defects. These were used to search for dose-sensitive dominant modifiers of pb function. Two identified interacting genes were the proto-oncogene Ras1 and its functional antagonist Gap1, prominent intermediaries in known signal transduction pathways. Ras1+ is a positive modifier of pb activity both in normal and ectopic cell contexts, while the Ras1-antagonist Gap1 has an opposite effect. A general role for Ras1 in homeotic function is likely, since Ras1+ activity also modulates functions of the homeotic loci Sex combs reduced and Ultrabithorax. Our data suggest that the modulation occurs by a mechanism independent of transcriptional control of the homeotic loci themselves, or of the Ras1/Gap1 genes. Taken together our data support a role for Ras1-mediated cell signaling in the homeotic control of segmental differentiation.

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