Leigh Syndrome-inducing Mutations Affect LRPPRC / SLIRP Complex Formation

ABSTRACT Mitochondria are essential organelles carrying their own genetic information which require specific gene expression processes. The leucine rich pentatricopeptide protein (LRPPRC) and its partner the SRA stem-loop interacting RNA binding protein (SLIRP) form a stable complex implicated in mRNA stability and polyadenylation. LRPPRC/SLIRP complex formation is still poorly characterized. We demonstrate that SLIRP interacts with the N-terminal region of LRPPRC in a RNA independent manner. We further show that the complex is stable in presence of high salt concentration. Point mutation and deletions found in the LRPPRC protein and responsible for the French-Canadian Leigh Syndrome (LSFC) are shown to affect complex formation in vitro . Our data are identifying the key region of LRPPRC involved in SLIRP association and showing the direct consequence of various LSFC mutations on the complex formation. Further experiments aiming at deciphering LRPPRC/SLIRP function(s) in vivo will benefit from our functional domain characterization.