Ribosomal slowdown mediates translational arrest during cellular division.
Global mRNA translation is transiently inhibited during cellular division. We demonstrate that mitotic cells contain heavy polysomes, but these are significantly less translationally active than polysomes in cycling cells. Several observations indicate that mitotic translational attenuation occurs during the elongation stage: (i) in cycling nonsynchronized cultures, only mitotic cells fail to assemble stress granules when treated with agents that inhibit translational initiation; (ii) mitotic cells contain fewer free 80S complexes, which are less sensitive to high salt disassembly; (iii) mitotic polysomes are more resistant to enforced disassembly using puromycin; and (iv) ribosome transit time increases during mitosis. Elongation slowdown guarantees that polysomes are retained even if initiation is inhibited at the same time. Stalling translating ribosomes during mitosis may protect mRNAs and allow rapid resumption of translation immediately upon entry into the G(1) phase.
Department of Cell Research and Immunology, George S Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel.
Gilad
G
Sivan
Nancy
N
Kedersha
Orna
O
Elroy-Stein
D000199:Actins / Q000378:metabolism; D000818:Animals; D002460:Cell Line; D054736:Elongation Factor 2 Kinase / Q000378:metabolism; D015852:Eukaryotic Initiation Factor-2 / Q000378:metabolism; D006801:Humans; D008938:Mitosis / Q000502:physiology*; D010766:Phosphorylation; D011132:Polyribosomes / Q000378:metabolism*; D014176:Protein Biosynthesis; D012333:RNA, Messenger / Q000378:metabolism*; D012492:Salts / Q000737:chemistry
D000199:Actins; D015852:Eukaryotic Initiation Factor-2; D012333:RNA, Messenger; D012492:Salts; D054736:Elongation Factor 2 Kinase