The mRNAs for cyclin A, c-myc and ribosomal proteins L4 and S6 are associated with cytoskeletal-bound polysomes in HepG2 cells.
Cytosolic, cytoskeleton and membrane fractions were extracted from HepG2 cells by a sequential detergent/salt extraction procedure. The cytosolic fraction contained 93% of the lactic dehydrogenase activity while the cytoskeleton fraction was enriched in actin and vimentin. The distribution of mRNAs for c-myc, glucose transporter 1, ribosomal proteins L4 and S6 and cyclin A were investigated by Northern hybridization of total RNA extracted from polysomes isolated from cytosolic, cytoskeleton and membrane fractions. The membrane-bound polysomes were enriched in the glucose transporter 1 mRNA and the cytoskeleton-bound polysomes were enriched in the mRNAs for the two ribosomal proteins, c-myc and cyclin A. The results suggest that the mRNAs for nuclear proteins are one class of mRNAs which are translated on polysomes associated with the cytoskeleton; this may be related to the requirement to transport the newly synthesized protein to the nucleus.
Hovland
R
R
Department of Biochemistry and Molecular Biology, University of Bergen, Norway.
Campbell
G
G
Pryme
I
I
Hesketh
J
J
D002462:Cell Membrane / Q000378:metabolism; D016213:Cyclins / Q000235:genetics* / Q000378:metabolism; D003599:Cytoskeleton / Q000378:metabolism; D006801:Humans; D011132:Polyribosomes / Q000378:metabolism; D016271:Proto-Oncogene Proteins c-myc / Q000235:genetics* / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism*; D038601:Ribosomal Protein S6; D012269:Ribosomal Proteins / Q000235:genetics* / Q000378:metabolism; D014407:Tumor Cells, Cultured
D016213:Cyclins; D016271:Proto-Oncogene Proteins c-myc; D012333:RNA, Messenger; D038601:Ribosomal Protein S6; D012269:Ribosomal Proteins; C056368:ribosomal protein L4