Polyribosomes associated with microfilaments in cultured lens cells.
Epithelial hamster lens cells, transformed by SV40 can be grown in suspension culture. Triton X-100 extraction of these cells grown under conditions when ribosome run off is blocked releases about 40% of the total amount of polyribosomes, designated as free- and loosely-bound polyribosomes. The Triton ghosts retain the remaining polysomal population which can be released by a combined treatment with deoxycholate and Nonidet P 40. Electron microscopic examination of the ghosts reveals microfilament-associated ribosome clusters next to a fraction of polysomes still attached to membranes. Preincubation of the cells with cytochalasin D prior to polyribosome isolation enables us to discriminate between these two latter polysome populations. The experiments indicate that about 25% of the polyribosomes are attached to microfilaments, while the remaining 35% are tightly bound to the membranes of the endoplasmic reticulum. When the different polyribosome classes were translated in a reticulocyte lysate, no significant differences could be observed in the patterns of the newly synthesized polypeptides. In all cases actin was one of the major products synthesized de novo.
D000818:Animals; D002458:Cell Fractionation / Q000379:methods; D002460:Cell Line; D002471:Cell Transformation, Neoplastic; D006224:Cricetinae; D015638:Cytochalasin D; D003572:Cytochalasins / Q000494:pharmacology; D003599:Cytoskeleton / Q000187:drug effects / Q000648:ultrastructure*; D004848:Epithelium / Q000648:ultrastructure; D007908:Lens, Crystalline / Q000648:ultrastructure*; D008647:Mesocricetus; D008854:Microscopy, Electron; D011132:Polyribosomes / Q000187:drug effects / Q000648:ultrastructure*; D014176:Protein Biosynthesis; D012156:Reticulocytes / Q000378:metabolism; D013539:Simian virus 40 / Q000235:genetics
D003572:Cytochalasins; D015638:Cytochalasin D