scholarly journals Introduction

Development ◽  
1987 ◽  
Vol 101 (Supplement) ◽  
pp. 1-1 ◽  
Author(s):  
Peter N. Goodfellow
Keyword(s):  
Sex Determination ◽  
Molecular Cloning ◽  
Genetic Control ◽  
Regulatory Genes ◽  
Control Gene ◽  
Developmental Control ◽  
Phenotypic Changes ◽  
Pleiotrophic Effects ◽  
Master Control ◽  
Testis Determining Gene

The current dogma describing the genetic control of development assumes a hierarchy of regulatory genes. In the simplest case, a master control gene directly regulates secondary genes which, in turn, regulate the expression of other genes. In principle the master control genes can be recognized by the pleiotrophic effects caused by mutation, however, complex phenotypic changes are also associated with mutations in many nonregulatory genes. The bestdescribed examples of control genes are from relatively simple organisms with well-developed genetics, for example Drosophila and Caenorhabdltis. Unfortunately, identification of developmental control genes in mammals has proved to be difficult, presumably because homeotic and similar mutations are lethal. There is, however, one well-defined developmental control gene in mammals: TDF or the testis-determining gene (the same locus is called Tdy in mouse). Molecular cloning of TDF will not only facilitate exploration of the fundamental questions of sex determination, but should also provide a model for genetic control of development.

Major sex-determining genes and the control of sexual dimorphism in Caenorhabditis elegans

Genome ◽  
1989 ◽  
Vol 31 (2) ◽  
pp. 625-637 ◽  
Author(s):  
Jonathan Hodgkin ◽  
Andrew D. Chisholm ◽  
Michael M. Shen
Keyword(s):  
Caenorhabditis Elegans ◽  
Sex Determination ◽  
X Chromosome ◽  
Germ Line ◽  
Cell Lineage ◽  
Regulatory Genes ◽  
Nematode Caenorhabditis Elegans ◽  
X Chromosomes ◽  
The Many ◽  
Lineage Analysis

Sex determination in Caenorhabditis elegans involves a cascade of major regulatory genes connecting the primary sex determining signal, X chromosome dosage, to key switch genes, which in turn direct development along either male or female pathways. Animals with one X chromosome (XO) are male, while animals with two X chromosomes (XX) are hermaphrodite: hermaphrodite development occurs because the action of the regulatory genes is modified in the germ line so that both sperm and oocytes are made inside a completely female soma. The regulatory genes are being examined by both genetic and molecular means. We discuss how these major genes, in particular the last switch gene in the cascade, tra-1, might regulate the many different sex-specific events that occur during the development of the hermaphrodite and of the male.Key words: nematode, Caenorhabditis elegans, sex determination, sexual differentiation, cell lineage analysis.

Clues from other animals and theoretical considerations

Development ◽  
1987 ◽  
Vol 101 (Supplement) ◽  
pp. 3-4
Author(s):  
Anne McLaren
Keyword(s):  
Sex Determination ◽  
Genetic Control ◽  
Y Chromosome ◽  
X Chromosome ◽  
X Chromosomes ◽  
The Third ◽  
Mouse Species ◽  
Primary Male ◽  
Theoretical Considerations ◽  
State Of Activity

In the first two papers of this volume, the genetic control of sex determination in Caenorhabditis and Drosophila is reviewed by Hodgkin and by Nöthiger & Steinmarin-Zwicky, respectively. Sex determination in both cases depends on the ratio of X chromosomes to autosomes, which acts as a signal to a cascade of règulatory genes located either on autosomes or on the X chromosome. The state of activity of the last gene in the sequence determines phenotypic sex. In the third paper, Erickson & Tres describe the structure of the mouse Y chromosome and the polymorphisms that have been detected in different mouse species and strains. As in all mammals, the Y carries the primary male-determining locus; autosomal genes may also be involved in sex determination, but they must act down-stream from the Y-linked locus.

The Drosophila eyes absent gene directs ectopic eye formation in a pathway conserved between flies and vertebrates

Development ◽  
1997 ◽  
Vol 124 (23) ◽  
pp. 4819-4826 ◽  
Author(s):  
N.M. Bonini ◽  
Q.T. Bui ◽  
G.L. Gray-Board ◽  
J.M. Warrick
Keyword(s):  
Gene Function ◽  
Compound Eye ◽  
Eye Development ◽  
Control Gene ◽  
Eyes Absent ◽  
Regulatory Loop ◽  
The Relationship ◽  
Eye Formation ◽  
Master Control

The fly eyes absent (eya) gene which is essential for compound eye development in Drosophila, was shown to be functionally replaceable in eye development by a vertebrate Eya homolog. The relationship between eya and that of the eyeless gene, a Pax-6 homolog, critical for eye formation in both flies and man, was defined: eya was found to be essential for eye formation by eyeless. Moreover, eya could itself direct ectopic eye formation, indicating that eya has the capacity to function as a master control gene for eye formation. Finally, we show that eya and eyeless together were more effective in eye formation than either gene alone. These data indicate conservation of the pathway of eya function between flies and vertebrates; they suggest a model whereby eya/Eya gene function is essential for eye formation by eyeless/Pax-6, and that eya/Eya can in turn mediate, via a regulatory loop, the activity of eyeless/Pax-6 in eye formation.

Identification of developmental regulatory genes in Aspergillus nidulans by overexpression.

Genetics ◽  
1995 ◽  
Vol 139 (2) ◽  
pp. 537-547 ◽  
Author(s):  
J F Marhoul ◽  
T H Adams
Keyword(s):  
Growth Inhibition ◽  
Aspergillus Nidulans ◽  
Genomic Dna ◽  
Regulatory Gene ◽  
Regulatory Genes ◽  
Dna Fragments ◽  
Expression Library ◽  
Phenotypic Changes ◽  
Inhibition Of Growth ◽  
Induction Sequence

Abstract Overexpression of several Aspergillus nidulans developmental regulatory genes has been shown to cause growth inhibition and development at inappropriate times. We set out to identify previously unknown developmental regulators by constructing a nutritionally inducible A. nidulans expression library containing small, random genomic DNA fragments inserted next to the alcA promoter [alcA(p)] in an A. nidulans transformation vector. Among 20,000 transformants containing random alcA(p) genomic DNA fusion constructs, we identified 66 distinct mutant strains in which alcA(p) induction resulted in growth inhibition as well as causing other detectable phenotypic changes. These growth inhibited mutants were divided into 52 FIG (Forced expression Inhibition of Growth) and 14 FAB (Forced expression Activation of brlA) mutants based on whether or not alcA(p) induction resulted in accumulation of mRNA for the developmental regulatory gene brlA. In four FAB mutants, alcA(p) induction not only activated brlA expression but also caused hyphae to differentiate into reduced conidiophores that produced viable spores from the tips as is observed after alcA(p)::brlA induction. Sequence analyses of the DNA fragments under alcA(p) control in three of these four sporulating strains showed that in two cases developmental activation resulted from overexpression of previously uncharacterized genes, whereas in the third strain, the alcA(p) was fused to brlA. The potential uses for this strategy in identifying genes whose overexpression results in specific phenotypic changes like developmental induction are discussed.

scholarly journals The Pax6 master control gene initiates spontaneous retinal development via a self-organising Turing network

Development ◽  
2020 ◽  
Vol 147 (24) ◽  
pp. dev185827
Author(s):  
Timothy Grocott ◽  
Estefania Lozano-Velasco ◽  
Gi Fay Mok ◽  
Andrea E. Münsterberg
Keyword(s):  
Model Organism ◽  
Control Gene ◽  
Tissue Interactions ◽  
Organ Systems ◽  
Necessary And Sufficient ◽  
Regenerative Therapies ◽  
Further Development ◽  
Master Control

ABSTRACTUnderstanding how complex organ systems are assembled from simple embryonic tissues is a major challenge. Across the animal kingdom a great diversity of visual organs are initiated by a ‘master control gene’ called Pax6, which is both necessary and sufficient for eye development. Yet precisely how Pax6 achieves this deeply homologous function is poorly understood. Using the chick as a model organism, we show that vertebrate Pax6 interacts with a pair of morphogen-coding genes, Tgfb2 and Fst, to form a putative Turing network, which we have computationally modelled. Computer simulations suggest that this gene network is sufficient to spontaneously polarise the developing retina, establishing the first organisational axis of the eye and prefiguring its further development. Our findings reveal how retinal self-organisation may be initiated independently of the highly ordered tissue interactions that help to assemble the eye in vivo. These results help to explain how stem cell aggregates spontaneously self-organise into functional eye-cups in vitro. We anticipate these findings will help to underpin retinal organoid technology, which holds much promise as a platform for disease modelling, drug development and regenerative therapies.

scholarly journals Genetic Control of Gonadal Sex Determination and Development

2019 ◽  
Vol 35 (5) ◽  
pp. 346-358 ◽  
Author(s):  
Isabelle Stévant ◽  
Serge Nef
Keyword(s):  
Sex Determination ◽  
Genetic Control

Genetic Control of Sex Determination

1987 ◽  
Vol 5 (03) ◽  
pp. 209-220 ◽  
Author(s):  
Joe Simpson
Keyword(s):  
Sex Determination ◽  
Genetic Control

scholarly journals ThePax6master control gene initiates spontaneous retinal development via a self-organising Turing network

2019 ◽  
Author(s):  
Timothy Grocott ◽  
Estefania Lozano-Velasco ◽  
Gi Fay Mok ◽  
Andrea E Münsterberg
Keyword(s):  
Control Gene ◽  
Embryonic Tissues ◽  
Tissue Interactions ◽  
Organ Systems ◽  
Necessary And Sufficient ◽  
Regenerative Therapies ◽  
Further Development ◽  
Master Control

AbstractUnderstanding how complex organ systems are assembled from simple embryonic tissues is a major challenge. Across the animal kingdom a great diversity of visual organs are initiated by a ‘master control gene’ calledPax6, which is both necessary and sufficient for eye development1–6. Yet precisely howPax6achieves this deeply homologous function is poorly understood. Here we show that vertebratePax6interacts with a pair of morphogen-coding genes,Tgfb2andFst, to form a putative Turing network7, which we have computationally modelled. Computer simulations suggest that this gene network is sufficient to spontaneously polarise the developing retina, establishing the eye’s first organisational axis and prefiguring its further development. Our findings reveal how retinal self-organisation may be initiated independent of the highly ordered tissue interactions that help to assemble the eyein vivo. These results help to explain how stem cell aggregates spontaneously self-organise into functional eye-cupsin vitro8. We anticipate these findings will help to underpin retinal organoid technology, which holds much promise as a platform for disease modelling, drug development and regenerative therapies.

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