Li Chunyi, Yang Fuhe, Xing Xiumei, Gao Xiuhua, Deng Xuming, Mackintosh Colin, Suttie James M
AgResearch Invermay Agricultural Centre, Mosgiel, New Zealand.
J Exp Zool B Mol Dev Evol. 2008 May 15;310(3):267-77. doi: 10.1002/jez.b.21210.
Heterotypic tissue interactions play an indispensable role in organ generation and regeneration. In contrast to the classic examples of tissue interactions prevailing in the formation of tetrapod limbs or pectoral fins that can only take place when the interactive tissues are in intimate contacts, the interactions in deer antler formation are novel in that the inducer and the responder are separated by a distance of 1-2 mm. This feature offers a unique opportunity to explore the mechanism underlying tissue interactions by permitting membrane insertion between the two interactive tissues. Four experiments were conducted in this study. The results showed that the impermeable membranes inhibited antler formation. In contrast, the permeable membrane (0.45 microm in pore size) substantially slowed pedicle growth and antler initiation but did not stop them. Interestingly, the impermeable membrane/sheath only slightly retarded antler elongation. Overall, our results demonstrate that interactions between the two interactive tissues, antlerogenic tissue and the overlying skin, are indispensable for first antler initiation and are achieved through diffusible molecules rather than direct physical contact. As the heterotypic tissue interactions are only required during antler initiation but not elongation, they must be transient in nature, and thus differ from those operating in limb/fin formation that can only be sustained by continuous interactions. A system in which organ development is achieved only through transient tissue interactions must be novel, if not completely unique. Understanding this system will undoubtedly enrich the knowledge in the field of tissue interactions and organogenesis.
异型组织相互作用在器官生成和再生中发挥着不可或缺的作用。与四足动物肢体或胸鳍形成过程中普遍存在的组织相互作用的经典例子不同，后者只有在相互作用的组织紧密接触时才会发生，而鹿茸形成过程中的相互作用则很新颖，因为诱导者和反应者之间相隔1-2毫米。这一特征为通过在两个相互作用的组织之间插入膜来探索组织相互作用的潜在机制提供了独特的机会。本研究进行了四项实验。结果表明，不可渗透膜抑制鹿茸形成。相比之下，可渗透膜（孔径0.45微米）显著减缓了角柄生长和鹿茸起始，但并未阻止它们。有趣的是，不可渗透膜/鞘仅略微延缓了鹿茸伸长。总体而言，我们的结果表明，鹿茸发生组织与覆盖其上皮肤这两个相互作用组织之间的相互作用对于首次鹿茸起始是不可或缺的，并且是通过可扩散分子而非直接物理接触实现的。由于异型组织相互作用仅在鹿茸起始期间需要，而在伸长期间不需要，它们本质上必定是短暂的，因此不同于肢体/鳍形成过程中发生的相互作用，后者只能通过持续的相互作用来维持。一个仅通过短暂组织相互作用实现器官发育的系统即使不是完全独特的，也必定是新颖的。理解这个系统无疑将丰富组织相互作用和器官发生领域的知识。
