Localization of olfactomedin-related glycoprotein isoform (BMZ) in the golgi apparatus of glomerular podocytes in rat kidneys.
Agene encoding olfactomedin-related glycoprotein was isolated from rat glomerulus despite its prior identification as a neuron-specific gene. The mRNA expression was remarkably intense in renal glomerulus and brain and faint in the lung and eye among rat systemic organs. Although the brain contained four mRNA variants (AMY, AMZ, BMY, and BMZ) transcribed from a single gene, the glomerulus, lung, and eye expressed only two variants (BMZ and BMY). The glycoprotein was intensely immunolocalized in glomerular podocytes and neurons by using an antibody against synthetic peptide of the M region, but weak in endothelial cells of the kidney and lung. Bronchiolar epithelial cells in the lung, and ciliary, corneal, and iris epithelial cells in the eye were also stained. Immunogold electron microscopy revealed selective localization of olfactomedin-related glycoprotein at the Golgi apparatus in podocytes. In glomerular culture, the staining was also intense at a juxtanuclear region in synaptopodin-positive epithelial cells of irregular shape (phenotypic feature of podocytes), whereas it was weak in synaptopodin-negative ones of cobblestone-like appearance (phenotypic feature of parietal epithelial cells of Bowman's capsule). Interestingly, Western blot analysis identified an intense band corresponding to BMZ isoform and another faint band corresponding to BMY isoform in the glomerulus, whereas the intensity of these two bands were nearly equal in the lung and eye. In the brain, four bands corresponding to four isoforms were observed apparently. Computer sequence analysis predicted coiled-coil structures in the secondary structure of the glycoprotein similar to those in Golgi autoantigens, suggesting significant roles in the unique functions of the Golgi apparatus in rat podocytes and neurons.
Kondo
Daisuke
D
Department of Medicine (II), Faculty of Medicine, Niigata University, Niigata, Japan.
Yamamoto
Tadashi
T
Department of Renal Pathology, Institute of Nephrology, Faculty of Medicine, Niigata University, Niigata, Japan.
Yaoita
Eishin
E
Department of Renal Pathology, Institute of Nephrology, Faculty of Medicine, Niigata University, Niigata, Japan.
Danielson
Patria E
PE
Department of Molecular Biology, The Scripps Research Institute, La Jolla, California.
Kobayashi
Hideyuki
H
Department of Medicine (II), Faculty of Medicine, Niigata University, Niigata, Japan.
Ohshiro
Kazufumi
K
Department of Renal Pathology, Institute of Nephrology, Faculty of Medicine, Niigata University, Niigata, Japan.
Funaki
Haruko
H
Department of Renal Pathology, Institute of Nephrology, Faculty of Medicine, Niigata University, Niigata, Japan.
Koyama
Y U
YU
Department of Renal Pathology, Institute of Nephrology, Faculty of Medicine, Niigata University, Niigata, Japan.
Fujinaka
Hidehiko
H
Department of Renal Pathology, Institute of Nephrology, Faculty of Medicine, Niigata University, Niigata, Japan.
Kawasaki
Katsutoshi
K
Department of Renal Pathology, Institute of Nephrology, Faculty of Medicine, Niigata University, Niigata, Japan.
Sutcliffe
J Gregor
JG
Department of Molecular Biology, The Scripps Research Institute, La Jolla, California.
Arakawa
Masaaki
M
Department of Medicine (II), Faculty of Medicine, Niigata University, Niigata, Japan.
Kihara
Itaru
I
Department of Renal Pathology, Institute of Nephrology, Faculty of Medicine, Niigata University, Niigata, Japan.
D000595:Amino Acid Sequence; D000818:Animals; D015153:Blotting, Western; D001921:Brain / Q000378:metabolism; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000378:metabolism; D016326:Extracellular Matrix Proteins / Q000235:genetics / Q000378:metabolism*; D005123:Eye / Q000378:metabolism; D006023:Glycoproteins / Q000235:genetics / Q000378:metabolism*; D006056:Golgi Apparatus / Q000378:metabolism* / Q000648:ultrastructure; D007678:Kidney Glomerulus / Q000378:metabolism* / Q000648:ultrastructure; D008168:Lung / Q000378:metabolism; D008854:Microscopy, Electron; D008856:Microscopy, Fluorescence; D008969:Molecular Sequence Data; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D017421:Sequence Analysis
D018076:DNA, Complementary; D016326:Extracellular Matrix Proteins; D006023:Glycoproteins; D012333:RNA, Messenger; C081451:olfactomedin