Hrp48, a Drosophila hnRNPA/B homolog, binds and regulates translation of oskar mRNA.
Establishment of the Drosophila embryonic axes provides a striking example of RNA localization as an efficient mechanism for protein targeting within a cell. oskar mRNA encodes the posterior determinant and is essential for germline and abdominal development in the embryo. Tight restriction of Oskar activity to the posterior is achieved by mRNA localization-dependent translational control, whereby unlocalized mRNA is translationally repressed and repression is overcome upon mRNA localization. Here we identify the previously reported oskar RNA binding protein p50 as Hrp48, an abundant Drosophila hnRNP. Analysis of three hrp48 mutant alleles reveals that Hrp48 levels are crucial for polarization of the oocyte during mid-oogenesis. Our data also show that Hrp48, which binds to the 5' and 3' regions of oskar mRNA, plays an important role in restricting Oskar activity to the posterior of the oocyte, by repressing oskar mRNA translation during transport.
Yano
Tamaki
T
European Molecular Biology Laboratory, Meyerhofstrasse 1, 69117 Heidelberg, Germany.
López de Quinto
Sonia
S
Matsui
Yasuhisa
Y
Shevchenko
Anna
A
Shevchenko
Andrej
A
Ephrussi
Anne
A
D000595:Amino Acid Sequence / Q000235:genetics; D000818:Animals; D001483:Base Sequence / Q000235:genetics; D016764:Cell Polarity / Q000235:genetics; D029721:Drosophila Proteins / Q000096:biosynthesis* / Q000235:genetics* / Q000378:metabolism*; D004331:Drosophila melanogaster / Q000166:cytology / Q000196:embryology / Q000235:genetics*; D034481:Heterogeneous-Nuclear Ribonucleoprotein Group A-B / Q000235:genetics* / Q000302:isolation & purification; D034441:Heterogeneous-Nuclear Ribonucleoproteins / Q000235:genetics* / Q000378:metabolism*; D008969:Molecular Sequence Data; D009865:Oocytes / Q000166:cytology / Q000254:growth & development / Q000378:metabolism; D009866:Oogenesis / Q000235:genetics; D011485:Protein Binding / Q000235:genetics; D014176:Protein Biosynthesis / Q000235:genetics*; D021381:Protein Transport / Q000235:genetics; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism*; D016601:RNA-Binding Proteins / Q000235:genetics; D012097:Repressor Proteins / Q000235:genetics
D029721:Drosophila Proteins; D034481:Heterogeneous-Nuclear Ribonucleoprotein Group A-B; D034441:Heterogeneous-Nuclear Ribonucleoproteins; C487427:Hrb27C protein, Drosophila; D012333:RNA, Messenger; D016601:RNA-Binding Proteins; D012097:Repressor Proteins; C091675:osk protein, Drosophila