Smit A B, Thijsen S F, Geraerts W P, Meester I, van Heerikhuizen H, Joosse J
Department of Biology, Vrije Universiteit, Amsterdam, The Netherlands.
Brain Res Mol Brain Res. 1992 Jun;14(1-2):7-12. doi: 10.1016/0169-328x(92)90003-t.
A cDNA clone encoding molluscan insulin-related peptide V (MIP V) was isolated from a cDNA library of the central nervous system (CNS) of the freshwater snail, Lymnaea stagnalis, using a heterologous screening with a previously identified MIP II cDNA. The MIP V cDNA encodes a preprohormone resembling the organization of preproinsulin, with a putative signal sequence, and an A and B chain, however, in this case connected by two distinct C peptide, C alpha and C beta, instead of one single C peptide. This phenomenon, which is shared by the MIP II precursor, represents a new development in the prohormone organization of peptides belonging to the insulin superfamily. The A and B chains of MIPs V, I and II, differ remarkably in primary structure; in contrast, the C alpha peptide domains are almost identical. MIP V has only limited sequence similarity with insulins and related peptides. Both MIP V and I exhibit structural features, which make them a unique class of the insulin superfamily. The MIP I, II and V genes are expressed in a single type of neuron: the growth controlling neuroendocrine light green cells of the Lymnaea CNS.
利用先前鉴定的MIP II cDNA进行异源筛选，从淡水蜗牛椎实螺中枢神经系统（CNS）的cDNA文库中分离出一个编码软体动物胰岛素相关肽V（MIP V）的cDNA克隆。MIP V cDNA编码一种前激素原，其结构类似于胰岛素原，具有一个假定的信号序列以及A链和B链，然而，在这种情况下，A链和B链由两个不同的C肽（Cα和Cβ）连接，而不是单个C肽。MIP II前体也存在这种现象，这代表了胰岛素超家族肽类前激素结构的新发展。MIP V、I和II的A链和B链在一级结构上有显著差异；相比之下，Cα肽结构域几乎相同。MIP V与胰岛素及相关肽的序列相似性有限。MIP V和I都具有结构特征使其成为胰岛素超家族中独特的一类。MIP I、II和V基因在单一类型的神经元中表达：即椎实螺中枢神经系统中控制生长的神经内分泌浅绿色细胞。
