The CPEB Protein Orb Specifies Oocyte Fate by a 3'UTR-Dependent Autoregulatory Loop.

TitleThe CPEB Protein Orb Specifies Oocyte Fate by a 3'UTR-Dependent Autoregulatory Loop.
Publication TypeJournal Article
Year of Publication2019
AuthorsBarr, J, Gilmutdinov, R, Wang, L, Shidlovskii, ii, Y, Schedl, P
JournalGenetics
Volume213
Issue4
Pagination1431-1446
Date Published2019 12
ISSN1943-2631
Keywords3' Untranslated Regions, Animals, Drosophila melanogaster, Drosophila Proteins, Female, Homeostasis, Microtubules, Mutation, Oocytes, Ovary, Protein Transport, RNA, Messenger, RNA-Binding Proteins, Synaptonemal Complex
Abstract

<p> encodes one of the two fly CPEB proteins. These widely conserved proteins bind to the 3'UTRs of target messenger RNAs (mRNAs) and activate or repress their translation. We show here that a positive autoregulatory loop driven by the gene propels the specification of oocyte identity in egg chambers. Oocyte fate specification is mediated by a 3'UTR-dependent mechanism that concentrates mRNAs and proteins in one of the two pro-oocytes in the 16-cell germline cyst. When the 3'UTR is deleted, mRNA and protein fail to localize and all 16 cells become nurse cells. In wild type, the oocyte is specified when and other gene products concentrate in a single cell in region 2b of the germarium. A partially functional 3'UTR replacement delays oocyte specification until the egg chambers reach stage 2 of oogenesis. Before this point, mRNA and protein are unlocalized, as are other markers of oocyte identity, and the oocyte is not specified. After stage 2, ∼50% of the chambers successfully localize in a single cell, and this cell assumes oocyte identity. In the remaining chambers, the autoregulatory loop is not activated and no oocyte is formed. Finally, maintenance of oocyte identity requires continuous activity.</p>

DOI10.1534/genetics.119.302687
Alternate JournalGenetics
PubMed ID31594794
PubMed Central IDPMC6893371