Laboratory for Sensory Circuit Formation, RIKEN Center for Developmental Biology, Kobe 650-0047 PRESTO, Japan Science and Technology Agency, Saitama 332-0012, Japan.
Dev Growth Differ. 2012 Apr;54(3):358-65. doi: 10.1111/j.1440-169X.2012.01334.x. Epub 2012 Mar 8.
Positional information is fundamental in development. Although molecular gradients are thought to represent positional information in various systems, the molecular logic used to interpret these gradients remains controversial. In the nervous system, sensory maps are formed in the brain based on gradients of axon guidance molecules. However, it remains unclear how axons find their targets based on relative, not absolute, expression levels of axon guidance receptors. No model solely based on axon-target interactions explains this point. Recent studies in the olfactory system suggested that the neural map formation requires axon-axon interactions, which is known as axon sorting. This review discusses how axon-axon and axon-target interactions interpret molecular gradients and determine the axonal projection sites in neural map formation.
位置信息在发育过程中至关重要。虽然在各种系统中，分子梯度被认为代表了位置信息，但用于解释这些梯度的分子逻辑仍存在争议。在神经系统中，基于轴突导向分子的梯度，在大脑中形成感觉图谱。然而，轴突如何根据相对而非绝对的轴突导向受体表达水平找到其靶标仍不清楚。没有单纯基于轴突-靶相互作用的模型可以解释这一点。嗅觉系统的最新研究表明，神经图谱的形成需要轴突-轴突相互作用，这被称为轴突分选。这篇综述讨论了轴突-轴突和轴突-靶相互作用如何解释分子梯度并确定神经图谱形成中的轴突投射部位。
