Sobue K, Yamamoto N, Yoneda K, Fujita K, Miura Y, Asai K, Tsuda T, Katsuya H, Kato T
Department of Anesthesiology and Resuscitology, Nagoya City University Medical School, Japan.
Biochim Biophys Acta. 1999 Dec 23;1489(2-3):393-8. doi: 10.1016/s0167-4781(99)00194-3.
Two cDNA isoforms of bovine aquaporin-4 (bAQP4-A and bAQP4-B) were newly isolated. Sequence analysis of both cDNAs revealed open reading frames of 972 (bAQP4-A) and 906 nucleotides (bAQP4-B) with deduced proteins of 323 (bAQP4-A) and 301 amino acid residues (bAQP4-B). Partial 5'-genomic sequence analysis showed that the 5'-noncoding sequences specific to bAQP4-A and -B transcripts were contained in distinct exons, exon 0 for bAQP4-A and new exon X for bAQP4-B. RNase protection assay demonstrated the definite expression of both isoforms in bovine brain. The deduced amino acid sequence of bAQP4-A was highly homologous to the human (97%), rat (95%), and mouse (93%) AQP4. Reverse transcription-PCR detected the expression of AQP4 mRNAs in bovine brain endothelial cells as well as in a variety of bovine organs such as brain, lung, spleen, and kidney. Northern blot analysis indicated that a 6.0 kb message is predominantly expressed in bovine brain and lung.
新分离出了牛水通道蛋白4的两种cDNA亚型（bAQP4 - A和bAQP4 - B）。对这两种cDNA的序列分析显示，bAQP4 - A的开放阅读框为972个核苷酸，bAQP4 - B的开放阅读框为906个核苷酸，推导的蛋白质分别为323个氨基酸残基（bAQP4 - A）和301个氨基酸残基（bAQP4 - B）。部分5' - 基因组序列分析表明，bAQP4 - A和 - B转录本特异的5' - 非编码序列包含在不同的外显子中，bAQP4 - A为外显子0，bAQP4 - B为新的外显子X。核糖核酸酶保护试验证明这两种亚型在牛脑中均有明确表达。bAQP4 - A推导的氨基酸序列与人（97%）、大鼠（95%）和小鼠（93%）的水通道蛋白4高度同源。逆转录 - 聚合酶链反应检测到水通道蛋白4的mRNA在牛脑内皮细胞以及多种牛器官如脑、肺、脾和肾中均有表达。Northern印迹分析表明，一条6.0 kb的信息主要在牛脑和肺中表达。
