COILING OF INTERMEDIATE FILAMENTS INDUCED BY MICRO-INJECTION OF A VIMENTIN-SPECIFIC ANTIBODY DOES NOT INTERFERE WITH LOCOMOTION AND MITOSIS

Abstract

Microinjection of polyclonal sheep anti-vimentin IgG purified by affinity chromatography into a rat [mammary carcinoma RMCD] fibroblastoid line leads to a specific reorganization of the cytoskeleton. Immunofluorescence microscopy shows that cytoplasmic microtubules and microfilaments are unaffected but intermediate filaments collapse and and are collected into a tight perinuclear cap containing antibody-crosslinked vimentin filaments. The crosslinking was further documented by EM after treatment with Triton X-100 and fertitin-labeled anti-sheep IgG. In spite of the presence of the caps, which are retained for .apprx. 30 h, cells show a normal morphology and are able to locomote. The collapsed intermediate filaments do not interfere with subsequent mitosis or with cytokinesis. After mitosis the capped filaments can be distributed either to both daughter cells or to only 1 of the 2 daughter cells. Rat kangroo kidney PtK2 cell line was also used in this study.