Barentsz, a new component of the Staufen-containing ribonucleoprotein particles in mammalian cells, interacts with Staufen in an RNA-dependent manner.
Staufen1, the mammalian homolog of Drosophila Staufen, assembles into ribonucleoprotein particles (RNPs), which are thought to transport and localize RNA into dendrites of mature hippocampal neurons. We therefore investigated whether additional components of the RNA localization complex besides Staufen are conserved. One candidate is the mammalian homolog of Drosophila Barentsz (Btz), which is essential for the localization of oskar mRNA to the posterior pole of the Drosophila oocyte and is a component of the oskar RNA localization complex along with Staufen. In this study, we report the characterization of mammalian Btz, which behaves like a nucleocytoplasmic shuttling protein. When expressed in the Drosophila egg chamber, mammalian Btz is still able to interact with Drosophila Staufen and reach the posterior pole in the wild-type oocyte, but does not rescue the btz mutant phenotype. Most interestingly, we show by immunoprecipitation assays that Btz interacts with mammalian Staufen in an RNA-dependent manner through a conserved domain, which encompasses the region of homology to the Drosophila Btz protein and contains a novel conserved motif. One candidate for an RNA that mediates this interaction is the dendritically localized brain cytoplasmic 1 transcript. In addition, Btz and Staufen1 colocalize within particles in the cell body and, to a more variable extent, in dendrites of mature hippocampal neurons. Together, our data suggest that the mRNA transport machinery is conserved during evolution, and that mammalian Btz is an additional component of the dendritic RNPs in hippocampal neurons.
Macchi
Paolo
P
Max-Planck-Institute for Developmental Biology, D-72076 Tübingen, Germany.
Kroening
Sven
S
Palacios
Isabel M
IM
Baldassa
Simona
S
Grunewald
Barbara
B
Ambrosino
Concetta
C
Goetze
Bernhard
B
Lupas
Andrei
A
St  Johnston
Daniel
D
Kiebler
Michael
M
D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D000818:Animals; D002478:Cells, Cultured; D003001:Cloning, Molecular; D017124:Conserved Sequence; D003712:Dendrites / Q000378:metabolism; D004330:Drosophila; D029721:Drosophila Proteins / Q000235:genetics* / Q000378:metabolism; D051379:Mice; D008969:Molecular Sequence Data; D009363:Neoplasm Proteins; D009474:Neurons / Q000378:metabolism; D029543:Nucleocytoplasmic Transport Proteins / Q000235:genetics / Q000378:metabolism; D009865:Oocytes / Q000378:metabolism; D009928:Organ Specificity; D017434:Protein Structure, Tertiary; D012333:RNA, Messenger / Q000378:metabolism; D016601:RNA-Binding Proteins / Q000235:genetics* / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D012261:Ribonucleoproteins / Q000235:genetics* / Q000378:metabolism*; D017386:Sequence Homology, Amino Acid
C476129:Casc3 protein, mouse; C476130:Casc3 protein, rat; D029721:Drosophila Proteins; D009363:Neoplasm Proteins; D029543:Nucleocytoplasmic Transport Proteins; D012333:RNA, Messenger; D016601:RNA-Binding Proteins; D012261:Ribonucleoproteins; C492187:Stau1 protein, mouse; C492186:Stau1 protein, rat; C433983:btz protein, Drosophila; C117884:staufen protein, mammalian; C069927:stau protein, Drosophila