Expression and localization of aquaporin 7 in normal skeletal myofiber.
We examined whether AQP7 molecules are expressed in the normal skeletal muscle at mRNA and protein levels. Gel electrophoresis of the reverse transcription-polymerase chain reaction (RT-PCR) product of total RNA samples of normal human or mouse muscles by using oligonucleotide primers for human or mouse AQP7 showed a band of 328 or 369 basepairs, which corresponded to the basepair length between two primers of AQP7. The nucleotide sequence of these RT-PCR products coincided with those of human and mouse AQP7. Immunoblot, immunohistochemical and immunoelectron-microscopic studies of the protein were done by using the rabbit antibody against the synthetic peptide of the N-terminal cytoplasmic domain of the human AQP7 molecule. Immunoblot analysis showed that the rabbit antibody against human AQP7 reacted with a protein of approximately 30 kDa molecular weight in extracts of normal human and mouse skeletal muscles, and normal mouse liver. Immunohistochemistry with our anti-AQP7 antibody showed an immunoreaction at the myofiber surface of type 1 and type 2 fibers in human muscles and of type 2 fibers in mouse muscles.
Department of Neurology, Showa University Fujigaoka Hospital, 1-30 Fujigaoka, Aoba-Ku, 227-8501, Yokohama, Japan. wakayama@showa-university-fujigaoka.gr.jp
Yoshihiro
Y
Wakayama
Masahiko
M
Inoue
Hiroko
H
Kojima
Takahiro
T
Jimi
Seiji
S
Shibuya
Hajime
H
Hara
Hiroaki
H
Oniki
D000818:Animals; D000906:Antibodies; D020346:Aquaporins / Q000096:biosynthesis* / Q000276:immunology; D015870:Gene Expression; D006801:Humans; D007150:Immunohistochemistry; D051379:Mice; D018485:Muscle Fibers, Skeletal / Q000378:metabolism*; D012333:RNA, Messenger / Q000096:biosynthesis
C114141:AQP7 protein, human; D000906:Antibodies; D020346:Aquaporins; D012333:RNA, Messenger