Related Experiment Video
Updated: Jul 8, 2026
06:27
Müller Glia Cell Activation in a Laser-induced Retinal Degeneration and Regeneration Model in Zebrafish
Published on: October 27, 2017
RGM is a repulsive guidance molecule for retinal axons
Philippe P Monnier1, Ana Sierra, Paolo Macchi
1Migragen AG, Spemannstrasse 34, 72076 Tuebingen, Germany.
Nature
|September 28, 2002
Summary
Scientists identified a novel repulsive guidance molecule (RGM) crucial for nervous system development. This molecule guides temporal retinal axons, ensuring proper connections in the brain.
Area of Science:
- Neuroscience
- Developmental Biology
- Molecular Biology
Background:
- Axon guidance is essential for establishing neural circuits during development.
- The retinotectal projection serves as a model system for studying axon guidance.
- Temporal retinal axons are guided by repulsive cues in the optic tectum.
Purpose of the Study:
- To clone and functionally characterize a novel axon guidance molecule.
- To investigate the role of this molecule in retinotectal projection development.
Main Methods:
- Cloning of a membrane-associated glycoprotein, termed repulsive guidance molecule (RGM).
- Analysis of RGM mRNA distribution in the embryonic optic tectum.
- In vitro experiments using recombinant RGM to assess growth cone collapse and axon guidance.
Main Results:
- RGM shares no sequence homology with known guidance cues.
- RGM mRNA exhibits a gradient distribution in the embryonic tectum.
- Recombinant RGM induces repulsive guidance of temporal retinal axons and growth cone collapse.
Conclusions:
- RGM is a novel repulsive guidance molecule involved in axon pathfinding.
- RGM plays a specific role in guiding temporal retinal axons during development.
- The graded expression of RGM in the tectum likely contributes to precise retinotectal mapping.
Related Concept Videos
01:22Activation and Inactivation of G Proteins
Heterotrimeric G proteins are guanine nucleotide-binding proteins. As the name suggests, heterotrimeric G proteins are composed of three subunits: alpha, beta, and gamma. They remain GDP-bound or GTP-bound inside the cells and switch between inactive/active states. The Gα subunit possesses the nucleotide-binding pocket that binds guanine nucleotides and switches between GDP or GTP-bound states. In contrast, the Gꞵ and Gγ subunits are always bound together with high affinity and are together...
01:21G-Protein Gated Ion Channels
GPCRs are primarily responsible for our sense of smell, taste, and vision. The binding of a sensory stimulus activates GPCR to stimulate effector proteins, many of which are ion channels in the sensory organs. GPCRs modulate the opening and closing of the target ion channels either directly by binding them, or by releasing second messengers that activate these channels. As ions move across the membrane, the membrane potential is altered, which induces an appropriate response.
Sensory organs,...
Sensory organs,...
01:20Anatomy of the Eyeball
The eye is a spherical, hollow structure composed of three tissue layers. The outer layer — the fibrous tunic, comprises the sclera — a white structure — and the cornea, which is transparent. The sclera encompasses some of the ocular surface, most of which is not visible. However, the 'white of the eye' is distinctively visible in humans compared to other species. The cornea, a clear covering at the front of the eye, enables light penetration. The eye's middle layer, the vascular tunic,...