Identification of growth hormone in the sea lamprey, an extant representative of a group of the most ancient vertebrates
Identification of growth hormone in the sea lamprey, an extant representative of a group of the most ancient vertebrates
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DOI：
10.1210/en.2002-220810
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发表时间：
2002-12-01
期刊：
影响因子：
4.8
通讯作者：
Sower, SA
中科院分区：
文献类型：
--
作者：
Kawauchi, H;Suzuki, K;Sower, SA
GH 在七鳃鳗中被发现，七鳃鳗是最古老的脊椎动物无颌类的现存代表。通过 RTPCR 从垂体中克隆了推定的 GH-cDNA。整个编码区包含 203 个氨基酸 (aa) 的开放阅读框。成熟蛋白也从垂体中分离出来，并通过凝胶过滤和反相 HPLC 进行分级。使用针对对应于前 GH 序列（氨基酸 29-45）的合成肽的兔抗血清，通过蛋白质印迹来监测推定的 GH。纯化蛋白的序列分析表明，前激素由22个氨基酸的信号肽和181个氨基酸的成熟蛋白组成，与鲟鱼GH具有25%的序列同一性。通过免疫组织化学鉴定产生位点是垂体近端远侧部背半部的细胞。在对七鳃鳗 IGF cDNA 进行 cDNA 克隆后，RT-PCR 显示七鳃鳗 GH 刺激七鳃鳗肝脏中的 IGF 表达。这是第一项在无颌类动物中鉴定出 GII/催乳素/生长抑素家族成员的研究。此外，GH 似乎是七鳃鳗中该激素家族的唯一成员。有证据表明，GH是GH家族分子进化中的祖先激素，刺激生长的内分泌机制在脊椎动物进化的早期阶段就已建立。
GH was identified in the sea lamprey, an extant representative of a group of the most ancient vertebrates, the Agnatha. A putative GH-cDNA was cloned from the pituitary by RTPCR. The entire coding region comprised an open-reading frame of 203 amino acids (aa). The mature protein was also isolated from pituitaries, and fractionated by gel filtration and reverse-phase HPLC. A putative GH was monitored by Western blotting with a rabbit antiserum against a synthetic peptide corresponding to pre-GH sequence (aa 29-45). Sequence analysis of the purified protein demonstrated that the prehormone consists of a signal peptide of 22 as and the mature protein of 181 aa, which shows 25% sequence identity with sturgeon GH. The site of production was identified through immunohistochemistry to be cells of the dorsal half of the proximal pars distalis of the pituitary. Following cDNA cloning of lamprey IGF cDNA, it was shown using RT-PCR that lamprey GH stimulates IGF expression in lamprey liver. This is the first study in which a member of the GII/prolactin/somatolactin family has been identified in an agnathan. In addition, GH appears to be the only member of this hormone family in the sea lamprey. Evidence suggests,that GH is the ancestral hormone in the molecular evolution of the GH family and that the endocrine mechanism for growth stimulation was established at an early stage of vertebrate evolution.