Cloning of two novel mammalian paralogs of relaxin/insulin family proteins and their expression in testis and kidney.
Cloning of two novel mammalian paralogs of relaxin/insulin family proteins and their expression in testis and kidney.
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DOI：
10.1210/mend.13.12.0388
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发表时间：
1999-12
影响因子：
--
通讯作者：
S. Hsu
中科院分区：
文献类型：
--
作者：
S. Hsu
基于与胰岛素和松弛素的序列同源性，我们从小鼠组织中分离到了两个新的胰岛素超家族基因。由于这些蛋白与松弛素和松弛素样因子(RLF或Ley I-L)有很高的相似性，因此被命名为Rif1(松弛素/胰岛素样因子1)和Rif2(松弛素/胰岛素样因子2)。RT-PCR后，分别从小鼠睾丸和卵巢中获得Rif1和Rif2的全长cDNA。此外，从人类睾丸中分离出了一个假定的人类Rif1同源基因。MRIF1、mRIF2和hRIF1的编码区分别为191、145和213个氨基酸，其氨基末端均含有典型的分泌信号序列。序列比较表明，RIF编码的蛋白质由一个长的C结构域连接的B亚基和A亚基组成，这些推测的配体的成熟蛋白与不同物种的松弛素、RLF和胰岛素关系最密切。Northern印迹分析表明，Rif1转录本的大小约为1.2kb，主要在小鼠和人的睾丸中表达。相反，2.0和1.2kb的Rif2信息在小鼠肾脏中优先表达，在睾丸、心脏和脑中表达较低。此外，免疫组织化学分析显示，Rif1在睾丸中的表达仅限于曲细精管周围的间质细胞。在肾脏中，Rif2信息定位于选定的Henle环上皮细胞。Rif1及其相关的RLF在睾丸间质细胞中的独特表达模式提示，这两种不同的胰岛素/松弛蛋白家族配体在睾丸功能中具有潜在的生理作用。此外，Rif2的空间表达模式提示了Rif2在肾脏生理学中的新作用。RIF多肽的发现扩大了松弛素样激素和胰岛素样激素家族的范围，并使未来能够阐明这些组织特异性因子的生理作用和激素机制。
Based on sequence homology to insulin and relaxin, we have isolated two novel genes of the insulin superfamily from mouse tissues. Because these proteins show a high similarity to relaxin and relaxin-like factor (RLF or Ley I-L), they were named as RIF1 (relaxin/insulin-like factor 1) and RIF2 (relaxin/insulin-like factor 2). After RT-PCR, full-length cDNAs of RIF1 and RIF2 were obtained from mouse testis and ovary, respectively. In addition, a putative human ortholog of RIF1 was isolated from human testis. The deduced coding regions of mRIF1, mRIF2, and hRIF1 were 191, 145, and 213 amino acids, respectively, and all three proteins contain a typical signal sequence for secretion at their amino terminus. Sequence comparison indicated that RIFs encode proteins consisting of B and A subunits connected by a long C domain peptide, and the deduced mature proteins of these putative ligands are most closely related to relaxin, RLF, and insulin from different species. Northern blot analysis showed that RIF1 transcripts are approximately 1.2 kb in size and are expressed mainly in testis of mouse and human. In contrast, RIF2 message of 2.0 and 1.2 kb are preferentially expressed in mouse kidney and are lower in testis, heart, and brain. In addition, immunohistochemical analysis showed that testis expression of RIF1 is restricted to interstitial cells surrounding seminiferous tubules. In kidney, the RIF2 message is localized to selected epithelial cells of loop of Henle. The exclusive expression pattern of RIF1 and related RLF in testis interstitial cells suggested potential physiological roles of these two distinct insulin/relaxin family ligands in testis function. Additionally, the spatial expression pattern of RIF2 suggests a novel role of RIF2 in nephrophysiology. Identification of RIF polypeptides expands the family of relaxin- and insulin-like hormones and allows future elucidation of the physiological role and hormonal mechanisms for these tissue-specific factors.