Claudin-11/OSP-based tight junctions of myelin sheaths in brain and Sertoli cells in testis.
Members of the newly identified claudin gene family constitute tight junction (TJ) strands, which play a pivotal role in compartmentalization in multicellular organisms. We identified oligodendrocyte-specific protein (OSP) as claudin-11, a new claudin family member, due to its sequence similarity to claudins as well as its ability to form TJ strands in transfected fibroblasts. Claudin-11/OSP mRNA was expressed in the brain and testis. Immunofluorescence microscopy with anti-claudin-11/OSP polyclonal antibody (pAb) and anti-neurofilament mAb revealed that in the brain claudin-11/OSP-positive linear structures run in a gentle spiral around neurofilament-positive axons. At the electron microscopic level, these linear structures were identified as the so-called interlamellar strands in myelin sheaths of oligodendrocytes. In testis, well-developed TJ strands of Sertoli cells were specifically labeled with anti-claudin-11/OSP pAb both at immunofluorescence and electron microscopic levels. These findings indicated that the interlamellar strands of oligodendrocyte myelin sheaths can be regarded as a variant of TJ strands found in many other epithelial cells, and that these strands share a specific claudin species, claudin-11/OSP, with those in Sertoli cells to create and maintain the repeated compartments around axons by oligodendrocytes.
Morita
K
K
Department of Cell Biology, Faculty of Medicine, Kyoto University, Sakyo-ku, Kyoto 606, Japan.
Sasaki
H
H
Fujimoto
K
K
Furuse
M
M
Tsukita
S
S
D000818:Animals; D001923:Brain Chemistry; D057167:Claudins; D005347:Fibroblasts / Q000737:chemistry / Q000648:ultrastructure; D005614:Freeze Fracturing; D015870:Gene Expression / Q000502:physiology; D007668:Kidney; D008297:Male; D008565:Membrane Proteins / Q000032:analysis* / Q000235:genetics*; D051379:Mice; D008969:Molecular Sequence Data; D009186:Myelin Sheath / Q000737:chemistry*; D009419:Nerve Tissue Proteins; D016900:Neurofilament Proteins / Q000032:analysis; D009836:Oligodendroglia / Q000737:chemistry; D012333:RNA, Messenger / Q000032:analysis; D051381:Rats; D017386:Sequence Homology, Amino Acid; D012708:Sertoli Cells / Q000737:chemistry*; D019108:Tight Junctions / Q000737:chemistry*
D057167:Claudins; C492354:Cldn11 protein, mouse; C492353:Cldn11 protein, rat; D008565:Membrane Proteins; D009419:Nerve Tissue Proteins; D016900:Neurofilament Proteins; D012333:RNA, Messenger