RT Journal Article
SR Electronic
T1 A molecular network of conserved factors keeps ribosomes dormant in the egg
JF bioRxiv
FD Cold Spring Harbor Laboratory
SP 2021.11.03.467131
DO 10.1101/2021.11.03.467131
A1 Friederike Leesch
A1 Laura Lorenzo-Orts
A1 Carina Pribitzer
A1 Irina Grishkovskaya
A1 Manuel Matzinger
A1 Elisabeth Roitinger
A1 Katarina Belačić
A1 Susanne Kandolf
A1 Tzi-Yang Lin
A1 Karl Mechtler
A1 Anton Meinhart
A1 David Haselbach
A1 Andrea Pauli
YR 2021
UL http://biorxiv.org/content/early/2021/11/03/2021.11.03.467131.abstract
AB Ribosomes are produced in large quantities during oogenesis and stored in the egg. However, the egg and early embryo are translationally repressed. Using mass-spectrometry and cryo-EM analyses of ribosomes isolated from zebrafish and Xenopus eggs and embryos, we provide molecular evidence that ribosomes transition from a dormant to an active state during the first hours of embryogenesis. Dormant ribosomes are associated with four conserved factors that form two modules and occupy functionally important sites of the ribosome: a Habp4-eEF2 module that stabilizes ribosome levels and a Dap1b/Dapl1-eIF5a module that represses translation. Dap1b/Dapl1 is a newly discovered translational inhibitor that stably inserts into the polypeptide exit tunnel. Thus, a developmentally programmed, conserved ribosome state plays a key role in ribosome storage and translational repression in the egg.Competing Interest StatementThe authors have declared no competing interest.