More new papers from Professor Barralle's group

Feiguin, F., Godena, V.K., Romano, G., D'Ambrogio, A., Klima, R., Baralle, F.E. Depletion of TDP-43 affects Drosophila motoneurons terminal synapsis and locomotive behavior. 2009. FEBS Lett. 583, 1586-1592

doi:10.1016/j.febslet.2009.04.019

Abstract: Pathological modifications in the highly conserved and ubiquitously expressed heterogeneous ribonucleoprotein TDP-43 were recently associated to neurodegenerative diseases including amyotrophic lateral sclerosis (ALS), a late-onset disorder that affects predominantly motoneurons [Neumann, M. et al. (2006) Ubiquitinated TDP-43 in frontotemporal lobar degeneration and amyotrophic lateral sclerosis. Science 314, 130–133, Sreedharan, J. et al. (2008) TDP-43 mutations in familial and sporadic amyotrophic lateral sclerosis. Science 319, 1668–1672, Kabashi, E. et al. (2008) TARDBP mutations in individuals with sporadic and familial amyotrophic lateral sclerosis. Nat. Genet. 40, 572–574]. However, the function of TDP-43 in vivo is unknown and a possible direct role in neurodegeneration remains speculative. Here, we report that flies lacking Drosophila TDP-43 appeared externally normal but presented deficient locomotive behaviors, reduced life span and anatomical defects at the neuromuscular junctions. These phenotypes were rescued by expression of the human protein in a restricted group of neurons including motoneurons. Our results demonstrate the role of this protein in vivo and suggest an alternative explanation to ALS pathogenesis that may be more due to the lack of TDP 43 function than to the toxicity of the aggregates.

D’Ambrogio, A., Buratti, E., Stuani, C., Guarnaccia, C., Romano, M., Ayala, Y.M., Baralle, F.E. Functional mapping of the interaction between TDP-43 and hnRNP A2 in vivo. 2009. Nucleic Acids Res. (in press)

doi: 10.1093/nar/gkp342

Abstract: Nuclear factor TDP-43 has been reported to play multiple roles in transcription, pre-mRNA splicing, mRNA stability and mRNA transport. From a structural point of view, TDP-43 is a member of the hnRNP protein family whose structure includes two RRM domains flanked by the N-terminus and C-terminal regions. Like many members of this family, the C-terminal region can interact with cellular factors and thus serve to modulate its function. Previously, we have described that TDP-43 binds to several members of the hnRNP A/B family through this region. In this work, we set up a coupled mini-gene/siRNA cellular system that allows us to obtain in vivo data to address the functional significance of TDP-43-recruited hnRNP complex formation. Using this method, we have finely mapped the interaction between TDP-43 and the hnRNP A2 protein to the region comprised between amino acid residues 321 and 366. Our results provide novel details of protein-protein interactions in splicing regulation. In addition, we provide further insight on TDP-43 functional properties, particularly the lack of effects, as seen with our assays, of the disease-associated mutations that fall within the TDP-43 321-366 region: Q331K, M337V and G348C.