Differential association of membrane-bound and non-membrane-bound polysomes with the cytoskeleton.
We report here a differential release of specific mRNAs from the cytoskeleton by cytochalasin D treatment. Non-membrane-bound polysomal mRNAs, such as histone mRNA and c-fos mRNA, are readily released from the cytoskeleton of HeLa cells during cytochalasin D treatment. Over 90% of H3 and H4 histone mRNA is associated with the cytoskeleton in control cells and only 25% in cells treated with cytochalasin D (40 micrograms/ml). In contrast, the membrane-bound polysomal mRNAs for HLA-B7 and chorionic gonadotropin-alpha are inefficiently released from the cytoskeletal framework by cytochalasin D alone; approximately 98% of the HLA-B7 mRNA in control cells is associated with the cytoskeleton, whereas approximately 65% of the HLA-B7 mRNA is retained on the cytoskeleton in cells treated with cytochalasin D (40 micrograms/ml). Disruption of polysome structure with puromycin during cytochalasin D treatment results in the efficient release of HLA-B7 mRNA from the cytoskeleton. Under these conditions, only 25% of the HLA-B7 mRNA remains associated with the cytoskeletal framework. Thus, membrane-bound polysomes appear to be attached to the cytoskeleton through a cytochalasin D-sensitive site as well as through association with the nascent polypeptide and/or ribosome. These results demonstrate a complex association of polysomes with the cytoskeleton and elements of the endoplasmic reticulum.
Zambetti
G
G
Department of Cell Biology, University of Massachusetts Medical Center, Worcester 01655.
Wilming
L
L
Fey
E G
EG
Penman
S
S
Stein
J
J
Stein
G
G
D008841:Actin Cytoskeleton / Q000187:drug effects / Q000648:ultrastructure; D002462:Cell Membrane / Q000378:metabolism / Q000648:ultrastructure; D015638:Cytochalasin D / Q000494:pharmacology; D003599:Cytoskeleton / Q000187:drug effects / Q000378:metabolism* / Q000648:ultrastructure; D006367:HeLa Cells; D006657:Histones / Q000235:genetics; D006801:Humans; D007425:Intracellular Membranes / Q000378:metabolism / Q000648:ultrastructure; D008854:Microscopy, Electron; D011132:Polyribosomes / Q000187:drug effects / Q000378:metabolism* / Q000648:ultrastructure; D011691:Puromycin / Q000494:pharmacology; D012333:RNA, Messenger / Q000187:drug effects / Q000235:genetics / Q000378:metabolism
D006657:Histones; D012333:RNA, Messenger; D015638:Cytochalasin D; D011691:Puromycin