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© The Rockefeller University Press,
0021-9525/1999//969 $5.00
The Journal of Cell Biology, Volume 147, Number 5,
, 1999 969-980
Original Article |
Centriolar Satellites
: Molecular Characterization, Atp-Dependent Movement toward Centrioles and Possible Involvement in Ciliogenesis
b Department of Cell Biology, Kyoto University Faculty of Medicine, Sakyo-ku, Kyoto 606-8501, Japan
c Department of Dermatology, Osaka University School of Medicine, Suita 565-0871, Japan
d Laboratory of Cell Biology, KAN Research Institute Inc., Kyoto Research Park, Shimogyo-ku, Kyoto 600-8815, Japan
e Department of Molecular Cell Biology, Institute of DNA Medicine, Jikei University School of Medicine, Minato-ku, Tokyo 105-0003, Japan
Tsukita Cell Axis Project, Exploratory Research for Advanced Technology, Japan Science and Technology Corporation, Kyoto Research Park, 17 Chudojiminami-machi, Shimogyo-ku, Kyoto 600-8813, Japan.81 (75) 315-642081 (75) 315-7912
nshiina{at}cell.tsukita.jst.go.jp
We identified Xenopus pericentriolar material-1 (PCM-1), which had been reported to constitute pericentriolar material, cloned its cDNA, and generated a specific pAb against this molecule. Immunolabeling revealed that PCM-1 was not a pericentriolar material protein, but a specific component of centriolar satellites, morphologically characterized as electron-dense granules,
70–100 nm in diameter, scattered around centrosomes. Using a GFP fusion protein with PCM-1, we found that PCM-1–containing centriolar satellites moved along microtubules toward their minus ends, i.e., toward centrosomes, in live cells, as well as in vitro reconstituted asters. These findings defined centriolar satellites at the molecular level, and explained their pericentriolar localization. Next, to understand the relationship between centriolar satellites and centriolar replication, we examined the expression and subcellular localization of PCM-1 in ciliated epithelial cells during ciliogenesis. When ciliogenesis was induced in mouse nasal respiratory epithelial cells, PCM-1 immunofluorescence was markedly elevated at the apical cytoplasm. At the electron microscopic level, anti–PCM-1 pAb exclusively labeled fibrous granules, but not deuterosomes, both of which have been suggested to play central roles in centriolar replication in ciliogenesis. These findings suggested that centriolar satellites and fibrous granules are identical novel nonmembranous organelles containing PCM-1, which may play some important role(s) in centriolar replication.
Key Words: centriole • centriolar satellites • fibrous granule • pericentriolar material-1 • ciliogenesis
© 1999 The Rockefeller University Press
The online version of this article contains supplemental material.Abbreviations used in this paper: aa, amino acids; AMP-PNP, adenylylimido diphosphate; GFP, green fluorescent protein; MT, microtubule; ORF, open reading frame; pAb, polyclonal antibody; PCM-1, pericentriolar material-1.
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