GSE68431
Chaperoning 5S RNA assembly by structural probing
In eukaryotes, three of the four ribosomal RNAs (rRNAs), the 5.8S, 18S and 25S/28S rRNAs, are  processed from a single pre-rRNA transcript and assembled into ribosomes. The fourth rRNA, the  5S rRNA, is transcribed by RNA polymerase III and is assembled into the 5S ribonucleoprotein  particle (5S RNP), containing ribosomal proteins Rpl5/uL18 and Rpl11/uL5, prior to its  incorporation into pre-ribosomes. In mammals the 5S RNP is also central regulator of the  homeostasis of the tumour suppressor p53. The nucleolar localisation of the 5S RNP and its  assembly into pre-ribosomes is performed by a specialised complex composed of Rpf2 and Rrs1 in  yeast or Bxdc1 and hRrs1 in humans. Here we report the structural and functional characterisation  of the Rpf2-Rrs1 complex alone, in complex with the 5S RNA and within pre-60S ribosomes. We  show that the Rpf2-Rrs1 complex contains a specialised 5S RNA E loop binding module, contacts  the Rpl5 protein and also contacts the ribosome assembly factor Rsa4 and the 25S RNA. We  propose that the Rpf2-Rrs1 complex establishes a network of interactions that guide the  incorporation of the 5S RNP in pre-ribosomes in the initial conformation prior to its rotation to form  the central protuberance found in the mature large ribosomal subunit. Overall design: Refer to individual Sample (2). Crac results for Rpf2-HTP and control strain BY4741 are provided