哺乳動物的瘦素(Leptin)是脂肪細胞的肥胖基因產物，具有調控食慾與能量平衡的重要功能。但是物種演化上更早的硬骨魚類瘦素卻有A、B兩型，我們對此差異感到興趣，希望利用斑馬魚模式生物比較兩種瘦素的異同之處。Leptin A和Leptin B的大小相當，分別為166和168個氨基酸，zlepA與zlepB的核?酸序列比對並無顯著相似性。但是zlepA與zlepB的氨基酸序列比對有30%相同性。本研究透過整體原位雜合法，觀察到斑馬魚發育期的瘦素表達時間與位置，並進行大腸桿菌合成瘦素重組蛋白試驗。實驗結果顯示zlepB並無母系效應，zlepA與zlepB在斑馬魚發育前期表達的時間點不太一樣，zlepA早於zlepB，而zlepB持續表達的時間較長，表達量也比zlepA強，其中3 dpf魚苗的胸鰭鰭芽位置偵測到zlepB，推測zlepB參與在鰭片的生長。已合成水溶性的瘦素重組蛋白(約20 KDa)，純化後未來可進行兩種瘦素調節體脂功能的相關研究。 Mammalian Leptin is expressed by adipocytes, Leptin plays a critical role in the control of appetite and energy balance. However, there were two types of Leptin A and B in the evolution of the earlier species of teleost fish. We were interested in the functional difference between the zlep A and B, by using the zebrafish model to compare the differences. zlep A and B consist of 166 and 168 amino acids, respectively. There was no significant similarity between the nucleotide sequences of zlepA and zlepB. However, the amino acid sequence alignments of zLepA and zLepB are 30% identical. In this study, through in whole-mount in situ hybridization, zLep expression time and spatial distribution were observed during zebrafish development. Furthermore recombinant protein Leptin were synthesized in E. coli. The results showed that zlepB had no maternal effect, zlepA and zlepB were not expressed in zebrafish at different time points, zlepA was earlier than zlepB, and zlepB was longer than zlepB. zlepB participate in the pectoral fin bud position at the 3 dpf larvae. Leptin has been synthesized water-soluble recombinant protein (about 20 kDa), purify the future can be two kinds of hormone-related fat body function studies.
