Related Experiment Video
Updated: Jun 15, 2026
07:40
Visualizing Ocular Morphogenesis by Lightsheet Microscopy Using rx3:GFP Transgenic Zebrafish
Published on: April 5, 2021
PHOX2A regulation of oculomotor complex nucleogenesis
Khaleda B Hasan1, Seema Agarwala, Clifton W Ragsdale
1Department of Neurobiology, The University of Chicago, Chicago, IL 60637, USA.
Development (Cambridge, England)
|March 11, 2010
Summary
The homeobox transcription factor PHOX2A can specify motoneuron cell fates and organize brain nuclei development. This study shows PHOX2A drives oculomotor complex formation and nerve generation in chick embryos.
Area of Science:
- Developmental Neuroscience
- Molecular Biology
- Neuroanatomy
Background:
- Brain nuclei are spatially organized neuronal collections crucial for vertebrate brain function.
- Mechanisms underlying the developmental generation of brain nuclei remain largely unknown.
- The chick midbrain oculomotor complex (OMC) serves as a model for studying nucleogenesis.
Purpose of the Study:
- To investigate the capacity of the homeobox transcription factor PHOX2A to generate a spatially organized midbrain oculomotor complex.
- To understand the role of PHOX2A in specifying motoneuron cell fates and orchestrating nuclear complex formation.
Main Methods:
- Forced expression experiments using exogenous Phox2a delivery to embryonic chick midbrain.
- Analysis of molecular programs, cell production, nerve generation, and cell migration patterns.
Main Results:
- Exogenous Phox2a delivery induced a complete OMC molecular program, producing visceral and somatic motoneurons.
- Phox2a overexpression led to the generation of ectopic motor nerves that innervated extraocular muscles.
- Ectopic motoneurons were directed to correct spatial positions, with visceral neurons near the ventricular surface and somatic neurons deeper in the midbrain.
Conclusions:
- PHOX2A is a key transcription factor capable of specifying motoneuron cell fates in the midbrain.
- PHOX2A orchestrates the spatial organization and construction of motoneuron nuclear complexes.
- This study provides insights into the developmental mechanisms of brain nuclei formation.
Related Concept Videos
02:24Regulation of Expression Occurs at Multiple Steps
Gene expression can be regulated at almost every step from gene to protein. Transcription is the step that is most commonly regulated. This involves the binding of proteins to short regulatory sequences on the DNA. This association can either promote or inhibit the transcription of a gene associated with the respective sequence.
Transcription results in the generation of precursor (pre-mRNA) that consists of both exons and introns, which needs further processing before being translated to a...
Transcription results in the generation of precursor (pre-mRNA) that consists of both exons and introns, which needs further processing before being translated to a...
02:24Regulation of Expression Occurs at Multiple Steps
Gene expression can be regulated at almost every step from gene to protein. Transcription is the step that is most commonly regulated. This involves the binding of proteins to short regulatory sequences on the DNA. This association can either promote or inhibit the transcription of a gene associated with the respective sequence.
Transcription results in the generation of precursor (pre-mRNA) that consists of both exons and introns, which needs further processing before being translated to a...
Transcription results in the generation of precursor (pre-mRNA) that consists of both exons and introns, which needs further processing before being translated to a...
01:23Regulation of Expression at Multiple Steps
The gene expression in cells is regulated at different stages: (i) transcription, (ii) RNA processing, (iii) RNA localization, and (iv) translation. Transcriptional regulation is mediated by regulatory proteins such as transcription factors, activators, or repressors—these control gene expression by initiating or inhibiting the transcription of genes. Once a precursor or pre-mRNA is produced, it undergoes post-transcriptional modification, including 5' capping, splicing, and the addition of a...
02:23Master Transcription Regulators
Master transcription regulators are regulatory proteins that are predominantly responsible for regulating the expression of multiple genes. Often these genes work in concert to drive a complex process. Activation of a master transcription regulator can lead to a cascade of transcriptional activation necessary for that outcome. These regulators can directly bind to the regulatory sequences of the various genes involved, or they can indirectly regulate transcription by binding to regulatory...
01:20Folliculogenesis
Folliculogenesis is the development of ovarian follicles, the specialized structures within the ovarian cortex where oogenesis, or egg development, occurs. This process is essential for female reproductive health and begins during fetal development when primordial follicles are formed. Each primordial follicle comprises a primary oocyte in the center, surrounded by a single layer of squamous pre-granulosa cells. These follicles remain dormant in late prophase I of meiosis until triggered by...
01:29Translational Regulation
Translational regulation in prokaryotes ensures efficient protein synthesis by controlling ribosome access to mRNA. This regulation is mediated by secondary RNA structures, including translational riboswitches, RNA thermometers, and small RNAs (sRNAs), which respond to intracellular and environmental signals to modulate gene expression.Translational RiboswitchesRiboswitches in the leader region of mRNAs can regulate translation by altering the accessibility of the Shine-Dalgarno (SD) sequence,...