A recombinant polypeptide is described which comprises at least one PUF RNA-binding domain capable of specifically binding to a cytosine RNA base. The PUF RNA-binding domain of the polypeptide comprises at least one RNA base-binding motif of the general formula X1X2X3X4X5X6X7X8X9X10X11 wherein X1 is selected from the group including glutamine (Q), valine (V), methionine (M), proline (P), glutamic acid (E), and lysine (K) X2 is selected from the group including histidine (H), phenylalanine (F), tyrosine (Y), and asparagine (N) X3 is selected from the group including glycine (G) and alanine (A) X4 is selected from the group including glycine (G), alanine (A), serine (S), threonine (T) and cysteine (C) X5 is selected from the group including arginine (R), tyrosine (Y), histidine (H), and asparagine (N) X6 is selected from the group including phenylalanine (F), leucine (L), and valine (V) X7 is selected from the group including isoleucine (I), leucine (L), and valine (V) X8 is arginine (R) X9 is selected from the group including leucine (L), lysine (K), arginine (R), glutamine (Q), and histidine (H) X10 is selected from the group including lysine (K), phenylalanine (F), alanine (A), cysteine (C), isoleucine (I), valine 1 (V), leucine (L), and methionine (M) and X11 is selected from the group including leucine (L), phenylalanine (F), isoleucine (I), and valine (V) and wherein the RNA base- binding motif is operably capable of specifically binding to a cytosine RNA base.La présente invention a pour objet un polypeptide de recombinaison qui comprend au moins un domaine de liaison à lARN PUF capable de se lier spécifiquement à une base cytosine de lARN. Le domaine de liaison à lARN PUF du polypeptide comprend au moins un motif de liaison à une base de lARN de la formule générale X1X2X3X4X5X6X7X8X9X10X11, dans laquelle X1 est choisi dans le groupe comprenant la glutamine (Q), la valine (V), la méthionine (M), la proline (P), lacide glutamique (E), et la lysine (K) X2 est ch
