Cloning of a novel water and urea-permeable aquaporin from mouse expressed strongly in colon, placenta, liver, and heart
Cloning of a novel water and urea-permeable aquaporin from mouse expressed strongly in colon, placenta, liver, and heart
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DOI：
10.1006/bbrc.1997.7664
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发表时间：
1997-11-17
影响因子：
3.1
通讯作者：
Verkman, AS
中科院分区：
文献类型：
--
作者：
Ma, TH;Yang, BX;Verkman, AS
基于与已知水通道蛋白的同源性，从小鼠中分离水通道蛋白型水通道。结果表明，该基因全长1447 bp，开放阅读框为783 bp，编码261个氨基酸的疏水蛋白，含有MIP家族成员保守的NPA基序。氨基酸比对显示AQP 8与植物水通道γ TIP的同源性最高（38%同一性），其次是哺乳动物水通道AQP 4（32%）和AQP 2（31%）。北方印迹分析表明，1.7 kb的转录本在胎盘>结肠>肝脏中强烈表达，与心脏相似。用AQP 8特异性引物进行RT-PCR和Southern杂交分析，结果显示AQP 8在上述组织中有转录，在胰腺、肺、肾、颌下腺、膈肌、睾丸、脾、胃和脑中也有转录。非洲爪蟾卵母细胞中AQP 8 cRNA的表达以汞敏感的方式将渗透水渗透性从（0.8 +/- 0.1）x 10（-3）cm/s增加到（22 +/- 3）x 10（-3）cm/s（10 ℃）。AQP 8对尿素也有渗透性，但对甘油无渗透性。使用cMyc标记的AQP 8对卵母细胞质膜表达进行归一化，表明单通道水渗透性为8.2 x 10-（14）cm（3）/s。AQP 8在水通道中是独特的，因为其尿素渗透性和其在胃肠道器官、胎盘和心脏中的强表达。(C)1997年学术出版社。
An aquaporin-type water channel was isolated from mouse based on homology to known aquaporins. A 1447 bp cDNA was sequenced (designated AQP8) with a 783 bp open reading frame encoding a 261 amino acid hydrophobic protein which contained the conserved NPA motifs of MIP family members. Amino acid alignment showed greatest homology of AQP8 to plant water channel gamma TIP (38% identity) followed by mammalian water channels AQP4 (32%) and AQP2 (31%). Northern blot analysis indicated a 1.7 kb transcript expressed strongly in placenta > colon > liver similar to heart. RT-PCR with AQP8-specific primers and Southern blot analysis showed AQP8 transcript in the above tissues and in pancreas, lung, kidney, submandibular gland, diaphragm, testis, spleen, stomach and brain. Expression of AQP8 cRNA in Xenopus oocytes increased osmotic water permeability from (0.8 +/- 0.1) x 10(-3) cm/s to (22 +/- 3) x 10(-3) cm/s (10 degrees C) in a mercurial-sensitive manner. AQP8 was also permeable to urea but not to glycerol. Normalization for oocyte plasma membrane expression using cMyc-tagged AQP8 indicated a single channel water permeability of 8.2 x 10-(14) cm(3)/s. AQP8 is unique among the water channels in terms of its urea permeability and its strong expression in gastrointestinal organs, placenta and heart. (C) 1997 Academic Press.