Molecular cloning of two bovine aquaporin-4 cDNA isoforms and their expression in brain endothelial cells.
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.
Sobue
K
K
Department of Anesthesiology and Resuscitology, Nagoya City University Medical School, Japan. kazsobue@med.nagoya-cu.ac.jp
Yamamoto
N
N
Yoneda
K
K
Fujita
K
K
Miura
Y
Y
Asai
K
K
Tsuda
T
T
Katsuya
H
H
Kato
T
T
D000595:Amino Acid Sequence; D000818:Animals; D051401:Aquaporin 4; D020346:Aquaporins / Q000235:genetics*; D001483:Base Sequence; D001921:Brain / Q000166:cytology / Q000378:metabolism*; D002417:Cattle; D003001:Cloning, Molecular; D018076:DNA, Complementary; D006801:Humans; D008969:Molecular Sequence Data; D020033:Protein Isoforms / Q000235:genetics*; D012333:RNA, Messenger / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D017386:Sequence Homology, Amino Acid
C496030:AQP4 protein, human; D051401:Aquaporin 4; D020346:Aquaporins; D018076:DNA, Complementary; D020033:Protein Isoforms; D012333:RNA, Messenger