Midkine (MDK) and Pleiotrophin (PTN) belong to a group of heparin-binding growth factors that has been shown to have pleiotropic functions in various biological processes during development and disease. Development of the vertebrate eye is a multistep process that involves coordinated interactions between neuronal and non-neuronal cells, but very little is known about the potential function of MDK and PTN in these processes. In this study, we demonstrate by section in situ hybridization, the spatiotemporal expression of MDK and PTN during ocular development in chick and mouse. We show that MDK and PTN are expressed in dynamic patterns that overlap in a few non-neuronal tissues in the anterior eye and in neuronal cell layers of the posterior eye. We show that the expression patterns of MDK and PTN are only conserved in a few tissues in chick and mouse but they overlap with the expression of some of their receptors LRP1, RPTPZ, ALK, NOTCH2, ITGβ1, SDC1, and SDC3. The dynamic expression patterns of MDK, PTN and their receptors suggest that they function together during the multistep process of ocular development and they may play important roles in cell proliferation, adhesion, and migration of neuronal and non-neuronal cells.

Midkine（MDK）和Pleiotrophin（PTN）属于一组肝素结合生长因子，已显示在发育和疾病的各种生物过程中具有多效性功能。脊椎动物眼睛的发育是一个多步骤过程，涉及神经元细胞与非神经元细胞之间的协同相互作用，但对于这些过程中MDK和PTN的潜在功能知之甚少。在这项研究中，我们通过部分原位杂交证明了小鸡和小鼠眼部发育过程中MDK和PTN的时空表达。我们展示了MDK和PTN它们以动态模式表达，该模式在前眼的一些非神经组织和后眼的神经元细胞层中重叠。我们显示，MDK和PTN的表达模式仅在小鸡和小鼠的少数组织中保守，但与它们的一些受体LRP1，RPTPZ，ALK，NOTCH2，ITGβ1，SDC1和SDC3的表达重叠。MDK，PTN及其受体的动态表达模式表明它们在眼部发育的多步过程中共同发挥作用，并且在细胞增殖，粘附以及神经元和非神经元细胞的迁移中可能发挥重要作用。