Biology subjects

Ephrussi, A.

Publications and source records attributed to Ephrussi, A..

3 recordsLinked to original sources

bioRxiv2018

All four double-stranded RNA binding domains of Staufen2 contribute to efficient mRNA recognition and transcript localization

Throughout metazoans, Staufen (Stau) proteins are core factors of mRNA localization particles. They consist of three to four double-stranded RNA binding domains (dsRBDs) and a C-terminal dsRBD-like domain. Mouse Staufen2 (mStau2) like Drosophila Stau (dmStau) contains four dsRBDs. Existing data suggest that only dsRBDs 3-4 are necessary and sufficient for mRNA binding. Here, we show that dsRBDs 1 and 2 of mStau2 bind RNA with similar affinities and kinetics as dsRBDs 3 and 4. While RNA binding by these tandem domains is transient, all four dsRBDs recognize their target RNAs with high stability. Rescue experiments in Drosophila oocytes demonstrate that mStau2 partially rescues dmStau-dependent mRNA localization. In contrast, a rescue with mStau2 bearing RNA-binding mutations in dsRBD1-2 fails, confirming the physiological relevance of our findings. In summary, our data show that the dsRBDs 1-2 play essential roles in the mRNA recognition and function of Stau- family proteins of different species.

biochemistry↗

bioRxiv2018

Transposon silencing in the Drosophila female germline ensures genome stability in progeny embryos

The piRNA pathway functions in transposon control in the germ line of metazoans. The conserved RNA helicase Vasa is an essential piRNA pathway component, but has additional important developmental functions. Here we address the importance of Vasa-dependent transposon control in the Drosophila female germline and early embryos. We find that transient loss of vasa expression during early oogenesis leads to transposon up-regulation in supporting nurse cells of the fly egg-chamber. We show that elevated transposon levels have dramatic consequences, as de-repressed transposons accumulate in the oocyte where they cause DNA damage. We find that suppression of Chk2-mediated DNA damage signaling in vasa mutant females restores oogenesis and egg production. Damaged DNA and up-regulated transposons are transmitted from the mother to the embryos, which sustain severe nuclear defects and arrest development. Our findings reveal that the Vasa-dependent protection against selfish genetic elements in the nuage of nurse cell is essential to prevent DNA damage-induced arrest of embryonic development.

developmental biology↗

bioRxiv2017

Enzymatic production of single molecule FISH and RNA capture probes

Arrays of singly-labelled short oligonucleotides that hybridize to a specific target revolutionized RNA biology, enabling quantitative, single molecule microscopy analysis and high efficiency RNA/RNP capture. Here, we describe a simple and efficient method that allows flexible functionalization of inexpensive DNA oligonucleotides by different fluorescent dyes or biotin using terminal deoxynucleotidyl transferase and custom-made functional group conjugated dideoxy-UTP. We show that 1) all steps of the oligonucleotide labelling - including conjugation, enzymatic synthesis and product purification - can be performed in a standard biology laboratory, 2) the process yields >90 %, often >95 % labeled product with minimal carry-over of impurities and 3) the oligonucleotides can be labeled with different dyes or biotin, allowing single molecule FISH or RNA affinity purification to be performed.\n\nGraphical abstract\n\nO_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=66 SRC=\"FIGDIR/small/107599_ufig1.gif\" ALT=\"Figure 1\">\nView larger version (20K):\norg.highwire.dtl.DTLVardef@a26162org.highwire.dtl.DTLVardef@a780d9org.highwire.dtl.DTLVardef@fc3a62org.highwire.dtl.DTLVardef@15d183c_HPS_FORMAT_FIGEXP M_FIG C_FIG

cell biology↗