Identification of a 195 kda protein in the striated rootlet: Its expression in ciliated and ciliogenic cells

Little is known about the molecular composition of the ciliary rootlet. We raised monoclonal antibodies to a crude preparation of striated rootlets is olated from the human oviduct. and obtained a clone (R4109) that specifical ly labeled the ciliary rootlets. Rootlets associated with the solitary cili um in secretory cells and fibroblasts were also labeled. R4109 identified a 195-kDa protein by immunoblotting. Ciliogenic cells in the oviduct epithel ium of young mice were labeled in the globular and/or granular pattern by R 4109 by immunofluorescence microscopy. Immunoelectron microscopy showed tha t they corresponded to fibrogranular complex and dense granule, respectivel y. The result demonstrated that the 195-kDa protein is a component common t o the striated rootlet and dense granule, and thus suggested that dense gra nules are involved in the rootlet formation. (C) 2000 Wiley-Liss, Inc.