Article

TDP-43 binds heterogeneous nuclear ribonucleoprotein A/B through its C-terminal tail - An important region for the inhibition of cystic fibrosis transmembrane conductance regulator exon 9 splicing

International Centre for Genetic Engineering and Biotechnology, Trieste, Italy.
Journal of Biological Chemistry (Impact Factor: 4.6). 12/2005; 280(45):37572-84. DOI: 10.1074/jbc.M505557200
Source: PubMed

ABSTRACT TDP-43 is a highly conserved nuclear factor of yet unknown function that binds to ug-repeated sequences and is responsible for cystic fibrosis transmembrane conductance regulator exon 9 splicing inhibition. We have analyzed TDP-43 interactions with other splicing factors and identified the critical regions for the protein/protein recognition events that determine this biological function. We show here that the C-terminal region of TDP-43 is capable of binding directly to several proteins of the heterogeneous nuclear ribonucleoprotein (hnRNP) family with well known splicing inhibitory activity, in particular, hnRNP A2/B1 and hnRNP A1. Mutational analysis showed that TDP-43 proteins lacking the C-terminal region could not inhibit splicing probably because they were unable to form the hnRNP-rich complex involved in splicing inhibition. Finally, through splicing complex analysis, we show that splicing inhibition mediated by TDP-43 occurs at the earliest stages of spliceosomal assembly.

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