Localization of Paracentrotus lividus bep
maternal mRNAs at the animal pole occurs by association
with the cytoskeleton and involves a 54-kDa protein, called
LP54, that is able to bind to the 3′ untranslated
regions (UTRs) of bep mRNAs. We describe here
the isolation and purification of this protein. Antibodies
raised against purified LP54 allowed us to establish its
localization in P. lividus eggs and embryos. This
localization coincides with the mRNAs with which it is
associated, that is, the animal pole in the egg, and, after
fertilization, the regions derived from this part of the
egg, and finally the oral ectoderm of the pluteus. Association
with the cytoskeleton was shown by the copurification of
LP54 in a microtubule preparation. Involvement in bep
mRNA localization was demonstrated by microinjection of
anti-LP54 antibodies in P. lividus eggs, which
caused alteration of spatial distribution of bep3
mRNA.