Differential gene expression of 36-kDa microfibril-associated glycoprotein (MAGP-36/MFAP4) in rat organs.
By using quantitative Western blot analysis and the real time polymerase chain reaction technique, we investigated the differential gene expression of microfibril-associated glycoprotein (MAGP-36) in rat organs. The gene was expressed highly in sites rich in elastic fibers, such as aorta, skin, and esophagus. However, MAGP-36 was also expressed highly in some other sites containing no elastic fibers. In lung and trachea, the expression levels of MAGP-36 mRNA were about seven times higher than those in other elastic tissues, although the protein abundances were almost at the same levels as other elastic tissues. MAGP-36 seemed to be secreted outside these organs. In brain, kidney, and spleen, although the expression levels of MAGP-36 mRNA were low, substantial amounts of MAGP-36 protein were detected. An immunohistochemical study revealed that MAGP-36 was present at the brush border of the S3 segment of proximal tubules in kidney. Since MAGP-36 is known to bind to mannan, MAGP-36 might be involved in mannose transport in the S3 segment. Thus, MAGP-36 might be multifunctional and present in a wide variety of sites in various organs.
Toyoshima
Tetsuhiko
T
Department of Structure and Functional Medicine, Faculty of Medicine, Kagawa University, 1750-1 Ikenobe, Miki-cho, Kagawa 761-0793, Japan. tetsu@kms.ac.jp
Ishida
Tetsuya
T
Nishi
Nozomu
N
Kobayashi
Ryoji
R
Nakamura
Takehiro
T
Itano
Toshifumi
T
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D015153:Blotting, Western; D001921:Brain / Q000378:metabolism; D003285:Contractile Proteins / Q000737:chemistry / Q000235:genetics*; D004547:Elastic Tissue / Q000378:metabolism*; D015870:Gene Expression; D006023:Glycoproteins / Q000737:chemistry / Q000235:genetics*; D007668:Kidney / Q000166:cytology / Q000378:metabolism; D008168:Lung / Q000378:metabolism; D020894:Microfibrils / Q000378:metabolism*; D008969:Molecular Sequence Data; D051381:Rats; D017207:Rats, Sprague-Dawley; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013154:Spleen / Q000378:metabolism; D014132:Trachea / Q000378:metabolism
D003285:Contractile Proteins; D006023:Glycoproteins; C530948:Mfap4 protein, rat