两栖类动物皮肤分泌物及其生物学适应意义——大蹼铃蟾皮肤分泌物蛋白质多肽组的启示

Amphibian Skin Secretions and Bio-adaptive Significance—Implications from Bombina maxima Skin Secretion Proteome

以大蹼铃蟾(Bombina maxima)为代表性物种,揭示了两栖类皮肤分泌物蛋白质多肽组丰富的分子和功能多样性。目前在大蹼铃蟾已发现的分子包括3类不同的抗菌肽、缓激肽、缓激肽增强肽和缓激肽拮抗肽、缓激肽基因相关肽、富含脯氨酸铃蟾肽及其基因相关肽、神经调节素U、Bv8肽、三叶型蛋白和蛋白酶抑制剂等。抗菌肽分子多样性及其形成机制、缓激肽及其基因相关肽功能和表达模式的多样性都较好地揭示了在多样的生态条件下,两栖类皮肤活性肽环境适应的分子基础及生物合成的调控机制。富含血红素辅基的白蛋白广泛分布在大蹼铃蟾皮肤外皮层细胞膜上和真皮海绵层内,表明它在皮肤的生理功能,如在呼吸、物质交换和渗透压调节中有重要作用。两栖类皮肤分泌物蛋白质多肽组,由于其分子结构的多样性、新颖性和哺乳类同系物的存在,在生物医学研究和天然药物开发中具有独特和不可替代的价值;同时,两栖类皮肤功能基因组具有多样性丰富、快速重组突变的特征,是探讨生物适应的基因基础、基因形成机制和进化特性等生物学基本问题的优秀模型。

The studies on Bombina maxima revealed the rich molecular and functional diversity of amphibian skin secretion proteins and peptides. Discovered peptides from B. maxima skin secretions are three classes of antimicrobial peptides, bradykinin analogs and its gene associated peptides with diverse biological functions, proline-rich bombesin and its gene associated peptides, neuromedin U analog, By8 peptides, trefoil factors and protease inhibitors. The molecular and functional diversity, gene formation mechanisms and expression patterns of the peptides in B. maxima skin well reflect the molecular basis of bio-adaptation of the frog in certain living environments. In addition, B. maxima albumin with a heme b cofactor is widely distributed around the membranes of epithelial layer cells and within the stratum spongiosum of dermis in the skin, indicating its important roles in skin physiological functions, like water economy, metabolite exchange and osmoregulation, etc. The extraordinary complexity of peptides found in amphibian skin, coupled with the high probability of their novel molecular structures and possible counterparts in mammals, make amphibians an important target group in biomedical research and new drug development. Meanwhile, amphibian skin functional genome should be a nice model to study molecular biology of bio-adaotation, new gene formation and evolution.